Automatic thermocouple positioner for use in vacuum furnaces

Patent · Thu Jan 01 00:00:00 EST 1981

OSTI ID:863944

Mee, David K ^[1]; Stephens, Albert E ^[1]

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1. Knoxville, TN

The invention is a simple and reliable mechanical arrangement for automatically positioning a thermocouple-carrying rod in a vacuum-furnace assembly of the kind including a casing, a furnace mounted in the casing, and a charge-containing crucible mounted in the furnace for vertical movement between a lower (loading) position and a raised (charge-melting) position. In a preferred embodiment, a welded-diaphragm metal bellows is mounted above the furnace, the upper end of the bellows being fixed against movement and the lower end of the bellows being affixed to support means for a thermocouple-carrying rod which is vertically oriented and extends freely through the furnace lid toward the mouth of the crucible. The support means and rod are mounted for relative vertical movement. Before pumpdown of the furnace, the differential pressure acting on the bellows causes it to contract and lift the thermocouple rod to a position where it will not be contacted by the crucible charge when the crucible is elevated to its raised position. During pumpdown, the bellows expands downward, lowering the thermocouple rod and its support. The bellows expands downward beyond a point where downward movement of the thermocouple rod is arrested by contact with the crucible charge and to a point where the upper end of the thermocouple extends well above the thermocouple support. During subsequent melting of the charge, the thermocouple sinks into the melt to provide an accurate measurement of melt temperatures.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: W-7405-ENG-26
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4281985
• OSTI ID: 863944
• Country of Publication: United States
• Language: English

Related Subjects

automatic
thermocouple
positioner
vacuum
furnaces
simple
reliable
mechanical
arrangement
automatically
positioning
thermocouple-carrying
rod
vacuum-furnace
assembly
including
casing
furnace
mounted
charge-containing
crucible
vertical
movement
loading
position
raised
charge-melting
preferred
embodiment
welded-diaphragm
metal
bellows
upper
fixed
affixed
support
means
vertically
oriented
extends
freely
lid
mouth
relative
pumpdown
differential
pressure
acting
causes
contract
lift
contacted
charge
elevated
expands
downward
lowering
arrested
contact
subsequent
melting
sinks
melt
provide
accurate
measurement
temperatures
melt temperature
pressure acting
vacuum furnace
vertically oriented
preferred embodiment
support means
differential pressure
accurate measurement
metal bellows
vertical movement
downward movement
mechanical arrangement
furnace assembly
accurate measure
/432/266/373/374/