ビルマ米袋積海上輸送における倉内実験(日本航海学会第16回講演会)

抄録

It is customarily required by surveyors to set wooden ventilators among rice bags carried by sea. Besides the researches made by the present authors there has been made no measurement or discussion of the quantitative efficiency of wooden ventilators and stowing methods of rice in bags in the ship's hold. Many of the changes in the quality of the rice may be the effects of the solar radiation, the temperature of sea water, atmosphere and ship's shell plates and the air condition in cargo spaces. The authors tried to find a better method of stowing bags of Burma rice and their proper management during the voyage. They measured the humidity, temperature, air velocity and moisture ratio of rice, setting many measuring points in and out of ship's hold. They noticed the following facts. 1. The temperature of the upper deck plates rose as high as 60℃ in the daytime and the heat flux into the hold reached 190Kcal/m^2.h. and there was almost no changes of the temperature inside the cargo throughout the voyage from Burma to Japan, though the temperature fell considerably as the ship neared Japan. 2. There was some air flow inside the wooden ventilators at all times through the voyage. And its average velocity was 0.1m/sec〜0.7m/sec. The velocity of the air flow was as great as 2m/sec inside the trench in the cargo. The continuous air flow inside the wooden ventilators, however, had little or no effect on the cargo temperature. 3. There was no gain of moisture ratio of the rice, either. But some condensation of moisture was seen on the skin of the ship, inevitably caused by the cooling down of the ship's shell plates near Japan. We can say that there was no changes of temperature and moisture ratio of rice in the ship's hold throughout this transportation from Burma to Japan.