Abstract: A rotary oil seal gas purge system for a rotary carburizing furnace, having a rotatable hearth in a furnace chamber containing a high carbon-potential furnace atmosphere comprising an endothermic carrier gas enriched with a hydrocarbon gas, features gas purge ports located adjacent to the oil seal(s) of the hearth for injecting non-carbon-enriched endothermic gas to purge the high carbon-potential furnace atmosphere from the area adjacent the seal(s) and prevent carbon precipitation into the seal(s). Also disclosed is an oil seal management system for a rotary carburizing furnace including a settling tank for accepting seal oil from the furnace oil seal(s), a pump supply tank for receiving oil from the settling tank, a pump for pumping oil from the pump supply tank through a heat exchanger and to the furnace oil seal(s), and a centrifuge for cleaning seal oil coming from the heat exchanger before returning it to the pump supply tank.

Abstract: An integrated continuous/batch furnace system for heat treating metal parts combines a continuous furnace system and a batch furnace system. The continuous furnace system includes a preheat furnace, a rotary carburizing furnace, an equalize/diffusion furnace, an oil quench, a press quench chamber and a slow cooling chamber. The batch furnace system includes a temper furnace, a carburize/quench/slow cool furnace, and a washer. A parts tray system for holding parts to be heat treated includes a parts tray for transporting parts through the continuous furnace system, and a parts tray assembly for transporting parts through the batch furnace system. The parts tray assembly includes two parts trays detachably coupled together with rigid U-shaped alloy chips.A method for heat treating trays of parts in an integrated continuous/batch furnace system includes determining whether to heat treat the parts with the continuous furnace system or the batch furnace system.