Abstract

A novel measurement system for dry rubber content in concentrated natural latex is presented and designed in this paper. The measurement system is composed of annular photoelectric sensor, laser diode, distance detector, two-stage amplifier module of weak photocurrent signal, signal conversion module, microprocessor and so on. According to the principle Lambert, the reflectivity of samples will be different when the dry rubber contents of samples are different. The reflectivity can be calculated by the reflection beam intensity, which could be characterized by the output voltage of the amplifier module. The distance between sensitive module and the surface of the sample is fixed by a lifting stage and the temperature of the sample is controlled by thermoelectric cooling modules (TEC). The system adopts indirect measurement method and confirms that the prediction performance of the binary linear standard equation, established by the data measured at the temperature 25°C and 30°C, is relatively good. Simultaneously, the experimental verification of the system is illustrated in this paper and the result shows that the dry rubber percentage content in concentrated latex can be measured rapidly and the real time application is effective. Furthermore, the anti-counterfeiting function can be realized in measurement of the adulterate latex.

Key words: Dry rubber content, photoelectric sensor, indirect measurement, concentrated latex.