Young engineers make waves overseas in design competition

PUBLISHED : Tuesday, 07 September, 2010, 12:00am
UPDATED : Tuesday, 07 September, 2010, 12:00am

A device designed by three mechanical engineering students from Polytechnic University that helps sort bottles and cans for recycling has reached the finals of an international competition.

The device, which automatically identifies different materials such as plastic, glass, iron and aluminium using only mechanical processes, came second in its group in the qualifying round of the International Student Design Contest organised by the American Society of Mechanical Engineers International.

It uses several layers of slopes inside a box and four metal sensors to sort the cans and bottles. Plastic bottles roll down the slopes and end up in a compartment, while glass bottles, due to their weight, push open a valve in the middle of one slope leading them to another compartment. Metal sensors, upon detecting metallic cans, trigger a door to close which prevents the cans from dropping into the non-metal compartments. A rod with a magnetic head pushes aluminium cans into a third compartment and also attracts iron cans, pulling them into a fourth compartment.

The students said it took them half a year to design the device and that time management had been their biggest challenge as they had to complete the project outside lesson time.

'We wasted two months on an initial design that failed to meet the requirements [of the competition],' said Kathy Lai Wai-ian, leader of the trio. 'Now I am really looking forward to the finals.'

Lo Kok-keung, an engineer with the university's mechanical engineering department and the team's adviser, said he was confident the group would be among the top three finalists. 'A simple design is a good design ... I have been coaching students taking part in this competition since 2003 and from my experience, Hong Kong students are comparable with the international level,' he said.

The three will compete with 18 teams from the United States, Singapore, India, Turkey and Lebanon in the finals in Canada in November.