METHOD AND DEVICE FOR FRACTIONATING POLYETHYLENE NAPHTHALATE

摘要

PROBLEM TO BE SOLVED: To fractionate polyethylene naphthalate(PEN) from other materials by emitting an electromagnetic beam to an article, and measuring the energy quantity of the transmitted or reflected electromagnetic beam. SOLUTION: An electromagnetic beam source 12 consisting of a lamp 30 put in a housing 32 emits an electromagnetic beam 14 of a wavelength band of about 350-450 nm. An electromagnetic beam 16 passed through an article 100 is incident on a first sensor 22 connected to a microprocessor 28, and the microprocessor 28 analyses the detection signal from the first sensor 22 to judge whether the article 100 is PEN or not. An interference filter 34 for passing only a light of a narrow wavelength band around about 380 nm is provided on the upstream side of the first sensor 22, to pass the electromagnetic beam 16 before it gets into the first sensor 22. The microprocessor 28 compares the energy quantities of the electromagnetic beam 16 and the electromagnetic beam 14 on the basis of the detection signal, and judges that the article 100 is PEN when the energy quantity of the electromagnetic beam 16 is rather low.