： Based on the practice of installing long distance and large diameter medium pressure vapor piping， in this paper， the causes and harm resulted in the deviation of the large spherical compensator were analyzed． The opti-mization procedure of the installation was， then， presented， by which the thermal expansion of the piping can occur freely and the thermal stress in the piping will be decreased
本文根据大直径长距离中压蒸汽管线安装工程的施工实践，着重对引起球形补偿器安装偏移量误差的因素及危害进行分析，优化安装程序和控制措施，保证管线的自由热膨胀，减少或消除管线运行中的热应力。