This invention involves an interferometer arranged to measure the distance to a movable object. The interferometer includes a main wave guide for radiating electromagnetic waves towards the object and for receiving the electromagnetic wave after reflection from the object, and a secondary wave guide system, including detectors coupled to the main wave guide in order to receive components of both the radiated and reflected waves. By appropriate positioning of the coupling between main and secondary wave guides, detectors in the secondary wave guide system can readily determine the distance of an object.
The invention relates to a type of proximity sensor. In one form, two sinusoidal signals travel along two transmission lines near an object. When the distance between one or both of the lines and the object changes, the speed of travel of one or both of the signals changes. There is a correlation between the speed change and the distance, thus allowing one to infer distance from speed change. One way to measure the speed change is to measure the phase relationship between the two signals. The invention can be used to measure clearances between turbine blades and turbine shrouds in gas turbine aircraft engines. Based on the measured clearance, other apparatus can direct hot or cold air upon the shroud to expand or shrink the shroud, thereby changing the clearance.
The invention relates to a type of proximity sensor. In one form, two sinusoidal signals travel along two transmission lines near an object. When the distance between one or both of the lines and the object changes, the speed of travel of one or both of the signals changes. There is a correlation between the speed change and the distance, thus allowing one to infer distance from speed change. One way to measure the speed change is to measure the phase relationship between the two signals.
The invention relates to a type of proximity sensor. In one form, two sinusoidal signals travel along two transmission lines near an object. When the distance between one or both of the lines and the object changes, the speed of travel of one or both of the signals changes. There is a correlation between the speed change and the distance, thus allowing one to infer distance from speed change. One way to measure the speed change is to measure the phase relationship between the two signals.
