Method of detecting impurities in molten resin utilizing scattering light and the shadows of the impurities
US5570181A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Oct 29, 1996 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2015/1497
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of detecting impurities in a molten resin. The molten resin is massed through a passage having a window through which light can pass. Light is emitted from a light source through the window and the molten resin flowing through the passage. Sensors are used to sense a shadow produced when the light from the light source is interrupted by an impurity contained in the molten resin. Finally, the size of the impurity is measured from the width of the shadow and the intensity of light of the shadow. Also, judgment is made that if optical signals obtained by detecting the light that has passed through the molten resin indicate that there exist bright areas around a dark area, the dark area is distinguished as a shadow of an impurity. Further, in order to judge the shape of an impurity with high accuracy and record its image, a plurality of the devices used in the above method or the device used in the above method and a conventional camera may be used in combination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.