Systems and methods for detecting anomalies on internal surfaces of hollow elongate structures using time domain or frequency domain reflectometry

Abstract

Systems and methods for detecting an anomaly on an internal surface of a hollow, elongate, metallic pipe structure. An anomaly detection system employs an access port, an antenna, a signal source, and a signal analyzer. The access port allows physical access to an interior of the pipe structure. The antenna extends into the interior of the pipe structure through the access port. The signal source is operatively connected to the antenna and is capable of causing the antenna to cause a test signal to be conducted along the pipe structure such that the anomaly reflects at least a portion of the test signal back towards the antenna as a reflected signal. The signal analyzer is operatively connected to the antenna to analyze, in a frequency domain, the reflected signal.

1 . An anomaly detection system for detecting an anomaly on an internal surface of a hollow, elongate, metallic pipe structure, the anomaly detection system comprising:
 an access port allowing physical access to an interior of the pipe structure;   an antenna extending into the interior of the pipe structure through the access port;   a signal source operatively connected to the antenna, where the signal source is capable of causing the antenna to cause a test signal to be conducted along the pipe structure such that the anomaly reflects at least a portion of the test signal back towards the antenna as a reflected signal; and   a signal analyzer operatively connected to the antenna, where the signal analyzer analyzes, in a frequency domain, the reflected signal.   
     
     
         2 . An anomaly detection system as recited in  claim 1 , in which the signal source is a vector network analyzer. 
     
     
         3 . An anomaly detection system as recited in  claim 2 , in which the signal analyzer is the vector network analyzer. 
     
     
         4 . An anomaly detection system as recited in  claim 1 , in which the antenna is oriented along electric field lines defined by the pipe structure. 
     
     
         5 . An anomaly detection system as recited in  claim 1 , in which the antenna is oriented along magnetic field lines defined by the pipe structure. 
     
     
         6 . An anomaly detection system as recited in  claim 1 , in which a propagating mode of the test signal is at least one of the TE 11  mode and the TM 01  mode. 
     
     
         7 . An anomaly detection system as recited in  claim 1 , in which a propagating mode of the test signal predetermined based on at least one of the anomaly, the pipe structure, and fluid within the pipe structure. 
     
     
         8 . An anomaly detection system as recited in  claim 1 , in which the signal analyzer compares the reflected signal with a baseline signal. 
     
     
         9 . An anomaly detection system as recited in  claim 1 , in which the antenna is coated with a dielectric material. 
     
     
         10 . An anomaly detection system as recited in  claim 1 , in which allowable voltage and field magnitudes associated with the test signal are selected to reduce adverse affects on the pipe structure and fluid within the pipe structure. 
     
     
         11 . An anomaly detection system as recited in  claim 1 , further comprising a sensor capable of ascertaining a direction of travel of the reflected signal. 
     
     
         12 . An anomaly detection system as recited in  claim 1 , further comprising a pipeline access system arranged at the access port, where the pipeline access system allows the antenna to be used while pressurized fluid is flowing through the pipe structure. 
     
     
         13 . An anomaly detection system as recited in  claim 12 , in which the pipeline access system allows the port to be sealed when pressurized fluid is flowing through the pipe structure. 
     
     
         14 . An anomaly detection system as recited in  claim 1 , further comprising a pipeline access system arranged at the access port, where the pipeline access system allows the antenna to be used when fluid is drained from the pipe structure. 
     
     
         15 . An anomaly detection system as recited in  claim 1 , in which at least a portion of the pipe structure is cylindrical. 
     
     
         16 . A method of detecting an anomaly on an internal surface of a hollow, elongate, metallic pipe structure, the method comprising the steps of:
 forming at least one access port to allow physical access to an interior of the pipe structure;   extending an antenna into the interior of the pipe structure through the access port;   causing the antenna to cause the pipe structure to conduct a test signal through the anomaly such that the anomaly causes a reflected signal to be transmitted back towards the antenna; and   analyzing the reflected signal received by the antenna in a frequency domain.   
     
     
         17 . A method as recited in  claim 16 , in which;
 causing the antenna to transmit a test signal comprises the step of sending a plurality of test signals such that the anomaly causes a plurality of reflected signals to be transmitted back towards the antenna; and   the step of analyzing the reflected signal comprises the step of analyzing at least some of the plurality of reflected signals.   
     
     
         18 . A method as recited in  claim 16 , further comprising the step of providing a pipeline access system operable in a test configuration for allowing the antenna to be used while pressurized fluid is flowing through the pipe structure. 
     
     
         19 . A method as recited in  claim 18 , further comprising the step of operating the pipeline access system in a closed configuration in which the port to be sealed when pressurized fluid is flowing through the pipe structure. 
     
     
         20 . A method as recited in  claim 16 , in which the step of analyzing the reflected signal further comprises the step of ascertaining a direction of travel of the reflected signal.