초록 ▼

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

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.

대표청구항 ▼

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

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.