Cooling water tank of plastic extruder

The cooling water tank comprises a water tank body, mounting blocks are fixed to the two sides of the upper surface of the water tank body, mounting grooves are formed in the side walls, close to each other, of the two mounting blocks, fixing blocks are slidably connected into the mounting grooves, mounting frames are fixed to the side walls of the fixing blocks, and sliding grooves are formed in the side walls of the mounting frames; a sliding block is slidably connected into the sliding groove, a guide roller is rotatably connected to the side wall of the sliding block, a driving assembly used for driving the sliding block to slide is mounted on the mounting frame, and a limiting assembly used for limiting the fixing block is mounted on the mounting block. When the position of the guide roller needs to be adjusted, a worker enables the guide roller to move to a proper position by sliding the mounting frame and the fixing block, then the fixing block is limited through the limiting assembly, the sliding prob