If the environment temperature is below freezing, should advance to pump into the hot steam, preheatingtreatment, and then to start the pump.
若环境温度低于冰点，应预先向泵内通入热蒸汽，进行预热处理，然后才可启动齿轮泵。
2
The effect of preheatingtreatment process of cold rolls on induction heat quenched structures and the effect of heating temperature and time on structure and hardness have been studied.
研究了轧辊的预备热处理工艺对感应加热淬火组织的影响，感应加热温度和时间对组织和硬度的影响。
3
A furnace with preheating equipment for water vapor is developed for surface oxidation treatment of hot work dies. This type furnace is successfully used in industry.