Twintex Drying Methods
Mon, Apr 5, 2010
Has Fiber Glass Industries done anything to improve the method of drying of Glass Polypro (Twintex)? The Twintex from France was not yellow but the Twintex manufactured by Wichata Fall’s had some issues in this regard.
Tags: Twintex question
Twintex was dried at Saint Gobain Vetrotex America in Wichita Falls, TX in direct fired natural gas ovens. The heating in these ovens was done by air coming in direct contact with natural gas burners. Polypropylene is known to discolor or “yellowing” when coming in direct contact with natural gas fumes due to the presence of containments in the natural gas such as oxides of nitrogen (NOx). In Wichita Falls the Twintex product was dried vertically on a power and free conveyor system that inhibited air flow through the inside of the roving. The hot air blown on the outside of the roving did not facilitate a uniform drying profile which gave variations in strand integrity.
At Fiber Glass Industries we purchased a new hot air oven that uses steam as the heating source. This new oven is dedicated for GLASS POLYPRO. Hot air blown across the steam coil heat exchanger keeps the product from ever coming in contact with natural gas fumes or its containments of NOx. The product at FGI is also dried horizontally which allows the hot air to circulate through the inside of the roving thus providing a more uniform drying profile which delivers a more uniform strand integrity.
Ken Weiss
We bought a new indirect fired dryer and the packages are on hangers like in France. This dryer is dedicated to only this product so we can get the optimum drying cycle. Wichita Falls had direct fired dryers where the products of combustion blown through the system yellowed the packages. Also the packs were conveyed in the dryer on a belt so that also retarded the drying on the bottom or top. Wichita Falls made good material, we are trying some incremental improvements.
John Menzel
Ken-can you expain this a little more?