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Magnetic Crystal Puller

IP.com Disclosure Number: IPCOM000097521D
Original Publication Date: 1961-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Weiser, K: AUTHOR [+3]

Abstract

The all quartz, seed holder crystal puller eliminates the use of soft graphite bearings which may be a source of contamination. The principle of the seed holder is that the torque produced by the friction of two quartz bearing surfaces is minimized by keeping the line of contact between the rotating part of the holder and the bearing as near as possible to the axis of rotation. Hence, instead of using the walls of the pulling chamber as the bearing surface for rotation, the seed holder carries its own bearing in the form of a quartz cup through the center of which a hollow tube extends.

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Magnetic Crystal Puller

The all quartz, seed holder crystal puller eliminates the use of soft graphite bearings which may be a source of contamination. The principle of the seed holder is that the torque produced by the friction of two quartz bearing surfaces is minimized by keeping the line of contact between the rotating part of the holder and the bearing as near as possible to the axis of rotation. Hence, instead of using the walls of the pulling chamber as the bearing surface for rotation, the seed holder carries its own bearing in the form of a quartz cup through the center of which a hollow tube extends.

The shaft of the seed holder passes through this hollow tube, and the walls of the cup touch the walls of the pulling chamber loosely. A piece of magnetizable metal, sealed into the seed holder, is in line with a horseshoe magnet outside the pulling chamber. Upon rotation of this magnet, the seed holder shaft rotates. Due to the inherent non-equilibrium position of a magnet in the center of the line joining the poles of the external magnet, the seed holder is pressed against one side of the pulling chamber. The wall of the bearing cup is thus pressed against the wall of the pulling chamber. The shaft of the seed holder is pressed against the bearing tube of the cup.

Because of the much greater moment arm of the frictional force between the two walls as compared to that between the shaft and the cup bearing, rotation takes place on the line of contact betwee...