Improvements in safety, energy, production and service life for roller hearth furnaces for annealing of steel, copper, and stainless tubing - (PPT)

摘要

This paper has application to seamless and welded tube manufacturers; including carbon steel normalized or annealed tubing, for copper annealed tube and coils, and stainless bright annealed products. Safety improvement via safety PLC integration, and convection cooling for hot product: As common in manufacturing, we start with safety topics. Industrial furnace safety of operation in steady state-, and in startup or shutdown mode are each very important. To prove this point, consider the potential damage caused by a furnace startup failure, as compared to failure of another tube making process such as a draw bench. The tube pointer fails; you simply get oil on the floor. The furnace fails, there can be an explosion where you may lose the entire building, and create significant personal liability. NFPA 86 2011 Standard for Ovens and Furnaces contains the main guidelines for furnace equipment safety. Innovations such as Safety PLC control systems have been incorporated in the most recent standards. Roller hearth furnaces typically fall under one of two classes in the standard. Class B is written for direct fired furnaces, such as stress relief anneal furnaces. Class C is written for atmosphere furnaces, most of which are radiant tube furnaces for higher temperatures such as normalizing anneals. The direct fired furnace has attention to the burner permissive and purging system, to avoid a chamber full of explosive gas due to products input to the burners. The atmosphere furnace has attention to the burner system, to the atmosphere admittance system, the atmosphere generator proper, vestibule burn-off, and nitrogen purging system. Because of increased number of interlocks for Class C furnaces and the furnace and atmosphere generator pairing, a safety PLC is commonly utilized for best practice.