NTU-Earthlink Solar Innovations 2004 : Re.Fuse

1. NTU-Earthlink Solar Innovations 2004 : Re.Fuse The Challenge: Design a mechanism that is able to separate waste into different categories (paper ,metal ,glass etc)

2. Overview Ferrous Metal + Non-Ferrous Metal + Plastic + Paper + Other Junk Ferrous metal removed by magnetic attraction Non- Ferrous Metal + Plastic + Paper + Other Junk Non -Ferrous metal removed by infra-red detection Plastic + Paper + Other Junk Plastic and paper removed by air currents Other Junk Separated by flotation Plastic Paper

3. Separation of Ferrous Metals • The rubbish is loaded on a conveyor belt and moved along until it reaches the roller lined with an electromagnet. • As it passes the roller, the electromagnet will attract the metal to it, causing it to be attached to the roller. • The metal then moves up with the roller and is deposited into the collection bin. • The collection slide is positioned very near the roller such that it will just scrape the metal off the roller as the metal approaches it. • The remaining scrap material is carried on the conveyor belt until it drops into the funnel-shaped collection bin. Animation

4. Separation of Non-Ferrous Metals Mechanism to extract non-ferrous metal • Waste is loaded onto a platform full of pistons • Heater heats up waste and metal • Metal gains heat faster as it is a good conductor of heat • Picture is taken by infra-red camera and it is sent to computer which identify the “hotspots” • Pistons surrounding “hotspots” are fired which encloses the non-ferrous metal of a higher temperature • Mechanical arms tilt the platform, resulting in the falling of other waste • The non-ferrous metals remain caged by pistons • Pistons is then retracted and metal pushed by a broom into collection bin • Process is repeated several times Model

5. Separation of Non-Ferrous Metals • Mechanism to operate piston • To fire the piston, the valve for that particular piston is opened and the pressure will force the piston to fire out. • To retract the piston, the pressure is lifted and the valve closed when the piston returns to its original position. • The tip of the pistons are coated with heat-resistant thermoform plastic, so that they themselves do not register as a ‘hotspot’

6. Removal of Paper and Plastic from remaining waste • The refuse is transported by conveyor belt into the separation chamber • The fan is operated at high speed so that paper and plastic in the refuse tend to fly up to the height of the trap door • Within a few seconds, the trapdoor is closed. Paper and plastic is then collected • Paper and plastic at the top of the chamber, and remaining refuse at the bottom of the chamber, are pumped out of the chamber by their respective outlets. Animation

7. Separation of plastic and paper • The mixture is dumped into a transparent plastic chamber filled with water. • Plastic materials float as they have a low density • Cloth which is porous, soaks up water, becomes dense, and then sinks. • However, plastic sheets could be trapped within the soaked cloth at the bottom. • Bubbles are blown into the container and it stick to the plastic, allowing it to float to the surface. • On the other hand, no bubbles stick to cloth. Model

8. Separation of plastic and paper • Air pump is switched off. • After the operator observes that cloth has settled at the bottom, the flaps are raised. Plastic and cloth are effectively separated. • Water is then drained so that plastic settles on the separation flaps. • After separation, the upper pipe drains the plastic together with out of the cylinder. Paper is easily removed together with the fine net lining at the base of the cylinder.

9. Benefits & Unique features • Environmentally friendly • Smooth transit from one separation stage to another • Handling of a large volume of refuse at any one time • High degree of automation

10. Application • Separation of recyclable materials • Leftover materials can be sent for incineration. Energy from incineration can contribute to power grid.

11. THE END NATIONAL JUNIOR COLLEGE Teacher in-charge: Ms Yee See Ling Team members: Tan Thong Lip Alvin Chan Li Yun Chan Wei Sheng Daniel Fang Kok Boon Yeo Shi Wei Jason