工厂中的压缩空气一般压力不高,用于夹紧的气缸为了保证产生足够的夹紧力,常常将气缸的径向尺寸做得很大。当径向尺寸受结构限制时,可采用右图所示的串联式多级气缸,它可将多活塞产生的推力集中作用在同一个活塞杆上。活塞杆上有两个通气孔道,分别接通各气缸的两腔。气缸之间采用密封垫,通过端盖和螺母（活塞杆）压紧密封。 Compressed air in the factory is generally not high pressure, the cylinder used to clamp in order to ensure adequate clamping force, often the radial size of the cylinder to do a lot. When the radial size is limited by the structure, the tandem multistage cylinder shown on the right is used to concentrate the thrust generated by multiple pistons onto the same piston rod. Piston rod has two ventilation channels, respectively, connected to the two chambers of each cylinder. Gaskets are used between the cylinders to compress the seal through the end caps and nuts (piston rod).