Monitoring device for crystal pulling apparatus

Claim 1

In a monitoring device for crystal pulling equipment in which crystals are pulled from a melt in a crucible disposed on a stand inside a high pressure drawing chamber and through the cover of which the drawing spindle of a crystal mount is led and in which the equipment stand, the high pressure drawing chamber and crystal mount are disposed one above each other symmetrical to the drawing axis, the upper portion of the high pressure drawing chamber forming a bulb which is provided with a plurality of observation windows which may be viewed using a common television camera the improvement in said observation windows comprising: a. a cooled tapped nipple in the drawing chamber; b. a high pressure-tight mount inserted in said cooled tapped nipple; c. a high pressure window sealed in the outside end of said mount; and d. a quartz rod sealed into said mount and extending through the inside end thereof, said quartz rod projecting freely into the drawing chamber with its end in the immediate vicinity of the melt in the zone of the drawing chamber where there is no substantial temperature drop relative to the temperature of the melt.