補(bu)償(chang)器(qi)習慣上也叫膨脹節，或(huo)(huo)(huo)伸縮節。由(you)構成其工作主(zhu)體的波(bo)紋管(guan)(guan)(guan)(guan)(guan)（一種(zhong)(zhong)彈性元件）和端管(guan)(guan)(guan)(guan)(guan)、支架、法蘭、導(dao)管(guan)(guan)(guan)(guan)(guan)等附件組成。 屬于(yu)一種(zhong)(zhong)補(bu)償(chang)元件。利用其工作主(zhu)體波(bo)紋管(guan)(guan)(guan)(guan)(guan)的有效伸縮變形，以吸收管(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等由(you)熱(re)脹冷縮等原因而產生(sheng)的尺寸(cun)變化，或(huo)(huo)(huo)補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等的軸向(xiang)、橫(heng)向(xiang)和角(jiao)向(xiang)位移。也可用于(yu)降噪減振(zhen)。在現代工業中用途廣泛。供熱(re)上，為了防止供熱(re)管(guan)(guan)(guan)(guan)(guan)道升溫時，由(you)于(yu)熱(re)伸長或(huo)(huo)(huo)溫度(du)應力而引起管(guan)(guan)(guan)(guan)(guan)道變形或(huo)(huo)(huo)破壞，需要在管(guan)(guan)(guan)(guan)(guan)道上設置(zhi)補(bu)償(chang)器(qi)，以補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)道的熱(re)伸長，從而減小管(guan)(guan)(guan)(guan)(guan)壁的應力和作用在閥(fa)件或(huo)(huo)(huo)支架結構上的作用力。