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Variable Constant-Gradient Furnace

IP.com Disclosure Number: IPCOM000098045D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Wong, MC: AUTHOR

Abstract

The top drawing shows diagrammatically the interior windings of a tube furnace which provides an adjustable gradient from L to R. The construction involves a double coil winding, a primary heating coil A superimposed by secondary coil B. The two coils have identical linearly varying output characteristics along their lengths, but are oppositely oriented. Secondary B is connected to a Powerstat so that its input power is regulated relatively with respect to coil A.

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Variable Constant-Gradient Furnace

The top drawing shows diagrammatically the interior windings of a tube furnace which provides an adjustable gradient from L to R. The construction involves a double coil winding, a primary heating coil A superimposed by secondary coil B. The two coils have identical linearly varying output characteristics along their lengths, but are oppositely oriented. Secondary B is connected to a Powerstat so that its input power is regulated relatively with respect to coil A.

The heating effect at various places along the furnace length L to R is derived from the total output of the coils at these places. A linear temperature drop (longitudinally) results. The gradient is continuously adjustable from zero (inputs to A and B the same) to that obtained from coil A alone (zero input to B) as illustrated on the chart. The temperature at one end of the furnace is maintained at a desired value for any gradient setting of the Powerstat.

As one way of constructing this tube furnace, coils of nichrome wires may be wound around a ceramic tube. The linearly varying heat output of each coil is achieved by continuously increasing the pitch of the winding as it proceeds from one end. Over the primary coil is spread a layer of furnace cement upon which is wound the secondary coil with its pitch variation oriented in the direction opposite to the variation of the primary coil.

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