Experience Sharing : Application of Dehumidified Drying System on Tube Extruding

Article by: Aiping Xie / Translation Jacky Huang

Shini has a customer from Kunming, Yunnan Province who is the Polymer Materials manufacturer and they are awarded as National Key Technology Enterprise. Their products include PVC-U feed pipe, PP-R heat and cold water pipe, PE tube, anti-priming pipe and bellows which are widely applied on construction engineering. In 2010, this company established new branch and new assembly lines are required. Based on their planning from material drying to conveying and molding, Shini tailored an economical proper project for them. And year-end of 2010 saw the contract signing with Shini group for purchasing a large scale dehumidified drying system.

Technical parameters

  • Material varieties: PVC-U virgin, bulk density is 0.5kg/L; moisture content before dehumidifying is 0.1 % and moisture content after dehumidifying is 0.02%.
  • Material handling: dehumidified drying, drying period is 1.5 hours. 
  • Total amount of material is 2,500kg/L.
  • After the central drying, material would be conveyed to extruders.

Planning description

DH-8000U heat insulated hopper works with SD-4000H-C-D honeycomb rotor dehumidifier, which adopts P.I. D. temperature controller to ensure the even drying temperature of material. Under ideal condition, silica gel honeycomb rotor is able to provide dry air with low dew-point. Air return filter and double coolers ensure a much lower air return temperature while honeycomb rotor is immune to dust contamination. Portable dew-point monitor is capable of keeping an eye on dew-point changes. Stainless steel and flange connection are both adopted; air return pipeline is equipped with cyclone dust collector to prolong lifespan of honeycomb rotor. One separate auto loader collocating with vacuum loader is adopted to feed material to hopper.

The dehumidified drying system began in March, 2011 and has been completed in the middle of month. To date, the process turns out to be stable and drying time can be shortened. The central drying is not only capable of saving labor and improving efficiency but reduce the site area, sparing more space for workshop management. All of Shini efforts are highly praised by mass customers.