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 (non-buried) 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.