Fluidized bed gas distributor system for elevated temperature operation

Abstract

A method and apparatus for the debonding and sand core removal of sand cores from cast parts, the heat treating of metal parts and the removal of organic contamination from metal parts, which is utilizing a fluid bed furnace having an improved fluidizing gas distributor which discharges fluidized gas in a downward direction away from the parts in the fluidized bed.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to the methods and apparatus for the debonding and sand core removal of sand cores from cast parts, the heat treating of metal parts and the removal of organic contamination from metal parts, and relates more specifically to an improved method and apparatus utilizing a fluid bed furnace equipped with an improved fluidizing gas distributor. BACKGROUND OF THE INVENTION [0002] In the casting of ferrous and non ferrous metal into parts, the cast part is formed by pouring the molten ferrous or non ferrous metal into a mold. When the part has internal openings or paths, sand cores are made using foundry sand and a binder to the shape of the internal openings or paths, and are positioned in the proper location in the mold. The molten metal is poured into the volume between the mold and the core(s) usually surrounding some or most of the core. When the metal solidifies, the mold is opened and the part is removed. In most ...

AI Technical Summary

Benefits of technology

The invention is a new way to distribute high temperature gas in a fluid bed furnace or reactor. The new system uses a piping array that is placed in the bed of solid particles. The gas is fed to the array and then released through small openings in the bottom. This design ensures that the gas is released at a point above the bed of solids, which allows for indirect heat transfer through the walls of the array. This results in a more uniform temperature in the lower part of the bed, which can improve the treatment of parts near the bottom of the furnace. The new system also reduces the likelihood of particles becoming trapped in the piping. Overall, this new method improves the efficiency and safety of fluid bed furnaces.

Problems solved by technology

In these cases, direct injection of fuel into the fluidized solids bed by Mechanism iii, cannot be employed due to combustion gases being present in the fluidized solids bed which has an adverse effect on the quality of the products.

The maximum rate of energy transfer to the gas fluidized solids bed possible by this mechanism, is limited by the maximum temperature the furnace fluidizing gas distribution tuyere system can withstand mechanically, and the maximum fluidizing velocity that can be applied to the solids being fluidized without excessive entrainment of solids in the fluidizing gas exiting from the furnace.

The primary disadvantage to the use of Mechanism i, is that in applications requiring high rates of energy input to the gas fluidized solids, the temperature of the fluidizing gas must be significantly higher than the temperature of the fluidized solids bed.

This high temperature can in some cases, damage the parts being processed if the parts come close to, or contact a tuyere.

In addition, there are typically small shavings, pieces, or chips of aluminum which fall from the parts being processed which find their way to the bottom of the fluid bed furnace and gradually accumulate over a period of time.

When these pieces approach the vicinity of a tuyere, or contact a tuyere, they are usually melted and gradually surround the tuyeres and impede the flow of air.

Images