Multi-layer fluid curtains for furnace openings

• Main Authors: NOWOTARSKI; MARK S, BARLOW; ALAN R, RILEY; MICHAEL F, SHARMA; SUDHIR K
• Format: Patent
• Language: English
• Published: 09.08.1994
• Edition: 5
• Subjects: BLASTING; CHEMISTRY; DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS,IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KINDOF FURNACE; FURNACES; FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; HEATING; KILNS; LIGHTING; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL ENGINEERING; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; OPEN SINTERING OR LIKE APPARATUS; OVENS; RETORTS; WEAPONS

An apparatus and method for providing a selected atmosphere at and within an opening to the interior volume of a furnace. Two or more paralleled diffusers adjacent to the furnace opening laminarly emit different fluids and provide a multilayer fluid curtain over the opening. The curtain has a composite modified Froude number from 0.05 to 10, and a thickness at emission of at least 5% of its extent in the flow direction. Partially covering the outside of the curtain is an optional, substantially flat, outer shield with an aperture coinciding with the furnace opening, which reduces the necessary flow rates of fluids. Optional side shields around the sides of the curtain also reduce the necessary fluid flow. A preferred diffuser comprises a porous tube in a housing with an outlet directed to emit fluid across the furnace opening. The outlet is covered with a screen to disperse the fluid flow and to protect the porous tube.