| 摘要 |
In a hot gas turbine engine a capacitive probe clearanceometer is employed to measure the clearance gap or distance between the continuous surface of a compressor or turbine wheel such as, for example, a shroud ring turbine and its confining casing under operating conditions. The probe positions a capacitor electrode at the inner surface of the casing adjacent the continuous surface path. Electrical power is supplied to the probe through an oscillator having a tuned circuit in which the probe is a component. A high frequency signal of the oscillator is amplitude modulated by changes in electrical capacitance between the probe capacitor electrode and the passing continuous surface. The modulated oscillator signal is processed to provide an electrical signal which is proportional to the distance between the casing and the continuous surface. A preferred combination of high temperature and contamination resistant metal and ceramic materials are combined in an improved gas tight braze sealed probe tip.
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