Studies on Through-flow Drying of Cocoons

Abstract

The mechanism of through-flow drying of cocoons was studied under various drying conditions and the measurement was taken of the actual length of silk thread reeled off a cocoon.The equipment employed in these experiments was as shown in Fig. 1. The experimental results are summarized in Table 1. The drying curve and the temperature distribution of a cocoon are illustrated in Table 1, as to each chrysalis, silk layer and internal space.From the temperature distribution study, it was made clear that the moisture of a cocoon is mostly contained in the chrysalis and the moisture in the silk layer is quickly lost in the first stage of drying. The temperature of the chrysalis was found to be higher than that of the wet bulb in a hot air.The effects of various factors on the drying rate are shown in Figs. 3-6. Observed pressure drops through the cocoon bed and mass transfer capacity coefficients calculated from the experimental data are shown in Figs. 7 & 8, which may be expressed by the following equations.(1)ha=30.8G0.43 (2)