Multistage centrifugal compressor connected by using motor outer shell

The invention discloses a multistage centrifugal compressor connected by using a motor outer shell. Impellers of centrifugal compressors are mounted at two ends of a motor shaft, and share one shaft with a motor. The centrifugal compressors at two ends of the motor shaft communicate through a medium channel embedded in the motor outer shell or a motor stator iron core. Diffusers and backflow machines of the centrifugal compressors are hollowed circular barrels opened in single surfaces, and are provided with holes in the centers and guide blades on the inner end surfaces; and medium dischargeholes are uniformly distributed in the periphery of an outer shell of the final-stage diffuser. 本发明公开了种用电机外壳相连接的多级离心压缩机，离心压缩机的叶轮分别安装在电机轴的两端，与电机共用根轴。电机轴两端的离心压缩机，通过嵌入在电机外壳或电机定子铁芯上的介质通道相连通。离心压缩机的扩压器、回流器均为单面开口的内空圆桶状，中心有孔，在内端面设置导流叶片，并且在末级扩器的外壳上圆周均布介质排出孔。