Inert-Atmosphere Furnace
Thomas P. Whaley Ethyl Corporation
for Laboratory Use
Baton Rouge, Louisiana
Many different types of inert-atmosphere furnaces are being used today in research on titanium, zirconium, etc., several of which have been described in t.he literature. Most of them are rather elaborate, however, and often they are expensive to construct. The inert-atmosphere furnace described below can he constructed from standard laboratory equipment or from items which can be fabricated easily. The basic heating unit is a standard (Hoskins) laboratory crucible furnace with a heating chamber 5 in. in diameter and 51/2in. deep; the furnace operates H
Argon
Inert-atmosphere furnoce. A. Verticol crucible furnoce. B. steel thermocouple well. C. Stainless rteei reactor (500-ml 0. ~tmospherechamber. E. Lid for atmosphere chamber. tentiometer. G. Rotameter (Rowmeter). H. Chromel-alumel couple.
Stoinles beaker). F. Pothermo-
on a standard 110-v, 60-cycle circuit and does not require special wiring. The atmosphere chamber is a piece of 4-in. mild steel pipe, 4'/? in. o.d., closed at. one end by welding to a 4'/%-in.diameter disc, and equipped for gas-purging by welding lengths of S/8-in. pipe as shown in the figure. A simple slip-fit lid is made of a piece of a/,& mild steel plate with a '/%-in. diameter hole in the middle. The atmosphere chamber iLconnected to a cylinder of compressed argon or helium by '/h.copper tubing, coiled as shown to permit flexibility in moving the chamber. The reaction chamber used for most experiments was a 500-ml stainless steel beaker, hut can be a large refractory crucible or any container which will withstand the operating temperature of the furnace. stainless steel tubing, closed a t one A length of end, and bent as shown in Figure 1, is inserted through the hole in the lid and serves as a combination stirrer and thermocouple well. The bent portion of the tube provides a handle for grasping the stirrer without encountering the hot zone directly over the furnace chamber. The thermocouple wire should be long enough to permit manipulation of the stirrer. This inert-atmosphere furnace has been used quite satisfactorily for laboratory reduction of metal oxides, dehydration of salt hydrates, melting of certain metals, and other high-temperature, atmospheric-pressure operations up to about 1000°C. The coiled length of flexiblecoDner tubine ~ e r m i tremoval s of the hot reactor if necessary, without interruption firrapid of the prot,ect,iveatmosphere flow. Q
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