XI'AN -- Robots have been dispatched to patrol an underground pipe network in the city of Xi'an, capital of Northwest China's Shaanxi province, according to local authorities.

The 350-kilometer underground pipe network is a project under construction, integrating various pipelines including electricity, telecommunications, gas and water supply.

The underground pipe network is an important part of the infrastructure of the city and will solve the problem of "zipper chains" on the road.

The robot "security guards," 0.8 meters in height, are able to patrol the underground project independently for 24 hours a day.

Equipped with environmental detecting sensors, the robots can monitor temperature and humidity, noxious gases, oxygen levels and smoke density, while providing illumination in real time.

They can automatically report to management personnel if they malfunction.

The patrolling robots can cover blind spots neglected by human workers and improve the management of the project.