1. special single cod extruder for polyolefin ,having high extruding velocity and effective plasticization. 2. Separation mixing cod specialized for polyolefin. 3. Specially designed three co-extruding die, reasonable channel, smooth outside and inside wall, and little internal stress. 4. Producing pipe limitΦ16-Φ160mm, manufacture velocity up to 12m/min. 5. May be used to produce HDPE silicon core tube, ordinary PP-R, PE and PEX pipes.