With the support from HKUST, our team transformed the freshwater pipe system of HKUST (GZ) into a unique “living-lab” with 57 access points, covering the entire 6.5 km-long network. The ductile iron pipes are 200 to 300 mm in diameter and are arranged in 5 main loops. The network includes 15 bends (with varying degree of curvature from 5 to 180 degrees), 20 junctions, and 5 pressure-reducing valves.
Fig. 1: Schematic of GZ-campus freshwater distribution system
Each pipe branch of the network has access points in the middle and at two extremities. The intermediate access point of a branch permits introduction of defects (e.g., insertion of small blockages at the scale of pipe thickness). Each upstream and downstream access point has tapped or tee’d ports for attaching low-frequency (LF) transducers as well as access ports for insertion or connection of high-frequency (HF) transducers (see Fig. 2).
Fig. 2: Schematic of a branch pipe at the GZ-campus water distribution system indicating the access points positioning and details
Part of the water network (about 800 m) passes through an underground tunnel with fully accessible (unburied) pipes. This part of the network can be utilized to install the pipe sections with metamaterial lining, named as "meta-pipe". Fig. 3 demonstrates the installation of meta-pipe inside the tunnel.
Fig. 3: Schematic of the redundant/twin pipe branch designed in the GZ-campus freshwater system inside the tunnel (exposed/unburied). The schematic indicates how the pipe section can be disconnected and replaced with a “meta-pipeline”
A mechanically operated device for inserting, deploying, and retrieving sensors/receivers through HF access points is currently under development (see Fig. 4). This device is designed to control radial positioning of sensors, which is a crucial operation for HF-imaging as it allows collection of the scattering data matrix needed for imaging. This positioning system consists of a bolt-screw assembly that allows translation of a 95 cm long, stainless-steel rod connected to a transducer holder. The screw rotation is achieved with a servomotor with a 0.1 mm accuracy in radial translation. The azimuthal rotation is performed by a waterproof stepper motor.
Fig. 4: SolidWorks design of the robotic arm for inserting and positioning HF transducers at access points.