Patent ID: 7869979
Filing Date: 2011-01-11
Classification: F01D,F05D,G01B,G01S

Abstract:
1. A method for determining a radial gap size between a rotating and a stationary component of a continuous-flow machine, comprising: emitting a source signal as a radio wave from a transmitting device arranged on a surface of the stationary component; reflecting the radio wave by a reflection structure arranged on the rotating component that rotates at a constant angular velocity about a rotation axis along a circular path having a coordinate origin P(0,0) with reference to a Cartesian coordinate system P(x,y) such that the reflection structure has a continuously varying position as it rotates along the circular path, wherein the reflected radio wave is modified as compared to the emitted radio wave; receiving the modified radio wave as a received signal by a receiving device arranged on the rotationally fixed component outside the circular path on an ordinate at point P(0, y transferring the received signal to an evaluation device; evaluating a difference between the source signal and the received signal; determining parameters of a path curve of the circular path of the rotating reflection structure based on the evaluated difference between the source signal and the received signal by measuring a velocity of the rotating reflection structure via a first derivative ds/d(φ) of the distance s and determining a rotation angle Δφ from the velocity function wherein the rotation angle Δφ is proportional to the gap size of the radial gap; and displaying the gap size of the radial gap based on the determined parameters of the path curve.