美国在两辆矿石车上试验采用隔热墙板,即钢板表面复盖以聚氨基甲酸酯泡沫塑料,防止散装货物在运输中冻结。以前曾用这种泡沫塑料作煤车和矿石车的外墙隔热层进行试验。美国起先曾采用敞车隔热,后来又研究了预加热、干燥、运输中加热以及在煤和 The United States experimented on two ores using insulation panels, that is, the steel panels were covered with polyurethane foam to prevent the bulk cargo from freezing in transit. This type of foam has previously been tested on the outer insulation of coal cars and ore cars. The United States first used gondola insulation, and later studied the pre-heating, drying, heating and transport in the coal and