Non-contacting inductively coupled displacement sensor system for detecting levels of conductive, non-magnetic liquids, and method of detecting levels of such liquids
First Claim
1. The method of sensing changes in the level of molten, electrically conductive, non-magnetic liquid selected from the group consisting of gallium arsenide and indium phosphide which is contained in a sealed chamber under pressure which comprises, in combination,(a) generating an oscillating current of frequency within the range of from about 1 MHz to about 100 MHz;
- (b) passing said current through a sending/receiving coil located at a distance of from about 0.125 to about 1 mm from the top surface of said liquid, to inductively couple said coil to said liquid; and
(c) sensing changes in the frequency in said oscillating current caused by changes in the gap between the top surface of said liquid and said coil;
whereby changes in the gap, which are caused by changes in the top level of said liquid, are indicated by changes in the frequency of said oscillating current.
1 Assignment
0 Petitions
Accused Products
Abstract
An inductance coil serves as a displacement sensor arranged in connection with a tuned circuit of an oscillator. Liquid level displacement in an LEC crystal growth environment is sensed as a frequency change in the oscillator circuit as compared to a set point value. The sensor is protected from the environment by an outer protective sheath of non-conductive, non-contaminating material such as boron nitride.
32 Citations
6 Claims
-
1. The method of sensing changes in the level of molten, electrically conductive, non-magnetic liquid selected from the group consisting of gallium arsenide and indium phosphide which is contained in a sealed chamber under pressure which comprises, in combination,
(a) generating an oscillating current of frequency within the range of from about 1 MHz to about 100 MHz; -
(b) passing said current through a sending/receiving coil located at a distance of from about 0.125 to about 1 mm from the top surface of said liquid, to inductively couple said coil to said liquid; and (c) sensing changes in the frequency in said oscillating current caused by changes in the gap between the top surface of said liquid and said coil; whereby changes in the gap, which are caused by changes in the top level of said liquid, are indicated by changes in the frequency of said oscillating current. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification