|
High Temperature Systems, Inc. 16755 Park Circle Drive Chagrin Falls, OH 44023 Phone: (440) 543-8271 Fax: (440) 543-8198 Email: Inquiry Form Web: www.hitemp.com |
 THE MECHANICS OF DROSSING The level of dross must first be determined before lowering the pump. Inserting a long handled rod with a flat disc welded to the end into the melt until dross is felt at the bottom will accomplish this task. There should be marks on the upper end of the rod to indicate depth and this determines how far the pump is lowered. Measurements should be taken at various locations in the kettle to determine a map of the bottom dross thickness. While using this rod to determine depth, it should also be used to determine hardness of the dross. If the dross is hard, the pump should be lowered to within 2" of the dross. Then when the pump motor is started the suction from the impeller will pull the whole pump assembly down another 2" which takes it to the surface of the dross. If the dross is soft, the pump should be lowered to the point where it actually touches the surface of the dross. In either case, before starting the pump, a long handled spade should be used to break up the hard dross and or move the soft or broken dross where the pump will first travel. This is a critical part of successful dross pumping. It is the entry point of the pump into the dross. As each pass is made, continuing to break the hard dross up with the spade tool is critical to a successful cleaning. Expect that several inches of dross will remain, as there is a balance between total cleaning and just transferring excessive metal. |