摘要 |
<p>Disclosed are a system and method for the accurately calibrated non-contact capacitive measurement of small distances between relatively movable elements. The system and method are particularly well-suited for use in environments of high temperature, pressure, and vibration, including in jet engines to measure the gap between fan blades and the engine wall. A sensor disposed in a housing wall receives constant bias voltage and forms a sensing capacitor with the moving targets, which move past the sensor. A blocking capacitor allows a signal generated at the sensor to pass to a constant gain amplifier, which amplifies the signal and passes the amplified signal to a computer for calculating the small distances between the relatively movable elements using the bias, voltage, the gain, and the maxima and/or minima of the amplified output signal.</p> |