4 research outputs found
An inverse validation for detecting pipe leaks with a TDR-based method
Recently, an innovative system based on time domain reflectometry (TDR) for the individuation of leaks in underground pipes has been proposed and validated. Starting from the results obtained so far, the present works aims at further investigating the practical applicability of the aforementioned system. In particular, the goal of this work is to assess the system in the detection of two close leaks (i.e. leakages that may occur on the same length of pipe). To this purpose, an experimental setup was arranged: two "leakage conditions" were imposed, and the position of the leaks were considered as unknown and calculated through the dedicated developed algorithm. Results show that, differently from traditional leak detection methods (in which the presence of a leak may "mask" the presence of other leaks), the TDR-based system successfully individuates and correctly localizes the presence of two leaks
Microwave reflectometric systems and monitoring apparatus for diffused-sensing applications
Most sensing networks rely on punctual/local sensors; they thus lack the ability to spatially resolve the quantity to be monitored (e.g. a temperature or humidity profile) without relying on the deployment of numerous inline sensors. Currently, most quasi-distributed or distributed sensing technologies rely on the use of optical fibre systems. However, these are generally expensive, which limits their large-scale adoption. Recently, elongated sensing elements have been successfully used with time-domain reflectometry (TDR) to implement diffused monitoring solutions. The advantage of TDR is that it is a relatively low-cost technology, with adequate measurement accuracy and the potential to be customised to suit the specific needs of different application contexts in the 4.0 era. Based on these considerations, this paper addresses the design, implementation and experimental validation of a novel generation of elongated sensing element networks, which can be permanently installed in the systems that need to be monitored and used for obtaining the diffused profile of the quantity to be monitored. Three applications are considered as case studies: monitoring the irrigation process in agriculture, leak detection in underground pipes and the monitoring of building structures
Uncertainty estimation in simultaneous measurements of levels and permittivities of liquids using TDR technique
Time-domain reflectometry (TDR) based on instruments
are commonly used for several monitoring methods,
particularly in soil moisture and volumetric water-content evaluation.
Furthermore, significant advantages of TDR methodology,
mostly related to the possible determination in real-time and to
a nondestructive approach of the spatial location and nature of
various objects, make this technique an appealing candidate for
a variety of environmental and industrial applications. In this
paper, we show that the suitable combination of TDR-detecting
functionalities can lead to a joint quantitative and qualitativemonitoring
method for liquid-control purposes, so that, in one shot, the
analysis of TDR data allow the measurement of liquid levels, the
determination of multiple interfaces in layered media, as well as
the evaluation of dielectric properties, thus opening challenging
perspectives for several monitoring applications, particularly in
fluid-processing-related industry. For such purposes, a detailed
analysis of the uncertainty of the proposed measurementmethod is
mandatory; hence, a metrological characterization of the method
is carried out, demonstrating that the presented technique is
definitely valid for simultaneously measuring levels and dielectric
constants of liquids, with uncertainties under 2%. Results
obtained for different liquid samples validate the approach on a
wide range of dielectric materials and demonstrate the robustness
and reliability of the proposed TDR technique