Method and apparatus for determining properties of a pipeline, in particular the position of a branch of a sewage pipeline
AssigneeHochschule Offenburg
InventorWerner Schröder
Life of this patent
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Abstract
A method for determining properties of a pipeline includes feeding a sound wave signal at a predetermined feed point into the pipeline so that the sound wave signal propagates in an axial direction of the pipeline. The frequency spectrum of the transmitted sound wave signal has a frequency component or a spectral range with a maximum frequency that is smaller than the lower limit frequency for the first upper mode. Reflected portions of the transmitted sound wave signal are detected as received sound wave signal and are evaluated with regard to the transmitted sound wave signal to determine at least the distance of each reflection site from the feed point.
Claims16
A method for determining properties of a pipeline, the method including:
- (a) feeding a transmitted sound wave signal at a feed point into the pipeline so that the transmitted sound wave signal propagates in a longitudinal axial direction of the pipeline, the frequency spectrum of the transmitted sound wave signal having a frequency component or a spectral range with a maximum frequency that is less than a lower limit frequency for a first upper mode capable of propagating in the pipeline;
- (b) detecting a received sound wave signal, the received sound wave signal including, for each sound wave reflection site along the pipeline, a respective reflected portion of the transmitted sound wave signal reflected within the pipeline at that sound wave reflection site;
- (c) feeding a velocity measurement sound wave signal into the pipeline in both directions over a known length within the pipeline, receiving the velocity measurement sound wave signal, measuring a respective travel time of the velocity measurement sound wave signal in both directions over the known length within the pipeline, and determining an observed speed of sound within the pipeline;
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- (d) while taking the observed speed of sound as an actual speed of sound of a fundamental mode at conditions within the pipeline, determining at least a distance of each sound wave reflection site from the feed point by evaluating the received sound wave signal with respect to the transmitted sound wave signal.
An apparatus for determining properties of a pipeline, the apparatus including:
- (a) a sound wave transmission unit for feeding a transmitted sound wave signal into the pipeline from a feed point, the frequency spectrum of the transmitted sound wave signal having a frequency component or a spectral range with a maximum frequency that is less than a lower limit frequency of a first upper mode capable of propagating in the pipeline;
- (b) a sound wave receiving unit for detecting a received sound wave signal, the received sound wave signal including, for each sound wave reflection site along the pipeline, a respective reflected portion of the transmitted sound wave signal reflected within the pipeline at that sound wave reflection site;
- (c) a measurement device including two sound wave transmission and receiving units separated by a predetermined distance and being operable for feeding a velocity measurement sound wave signal into the pipeline in both directions between the two sound wave transmission and receiving units;
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- (d) a control and evaluation unit operably connected to the measurement device, the sound wave transmission unit, and the sound wave receiving unit, and being operable to (i) determine an observed speed of sound within the pipeline based on travel time of the velocity measurement sound wave signal between the two sound wave transmission and receiving units, to (ii) control the sound wave transmission unit, and to (iii), taking the observed speed of sound as an actual speed of sound of a fundamental mode at conditions within the pipeline, determine at least a distance of each sound wave reflection site from the feed point by evaluating the received sound wave signal with respect to the transmitted sound wave signal.
Dependencies are inferred from the claim text.