補(bu)(bu)償(chang)(chang)器(qi)習慣上也叫膨脹節(jie)，或伸縮節(jie)。由構成其(qi)工作主體的波紋管(guan)(guan)(guan)（一(yi)種彈(dan)性元件）和端(duan)管(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)等(deng)附(fu)件組成。 屬于(yu)一(yi)種補(bu)(bu)償(chang)(chang)元件。利用(yong)其(qi)工作主體波紋管(guan)(guan)(guan)的有(you)效(xiao)伸縮變(bian)(bian)形，以(yi)吸收管(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)、容(rong)器(qi)等(deng)由熱(re)脹冷縮等(deng)原(yuan)因(yin)而產生(sheng)的尺(chi)寸變(bian)(bian)化，或補(bu)(bu)償(chang)(chang)管(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)、容(rong)器(qi)等(deng)的軸向(xiang)(xiang)(xiang)、橫向(xiang)(xiang)(xiang)和角向(xiang)(xiang)(xiang)位(wei)移(yi)。也可用(yong)于(yu)降(jiang)噪減振(zhen)。在(zai)(zai)現代工業(ye)中用(yong)途(tu)廣(guang)泛(fan)。供(gong)(gong)熱(re)上，為(wei)了防止供(gong)(gong)熱(re)管(guan)(guan)(guan)道升溫時(shi)，由于(yu)熱(re)伸長或溫度應力(li)而引起管(guan)(guan)(guan)道變(bian)(bian)形或破壞(huai)，需要在(zai)(zai)管(guan)(guan)(guan)道上設置(zhi)補(bu)(bu)償(chang)(chang)器(qi)，以(yi)補(bu)(bu)償(chang)(chang)管(guan)(guan)(guan)道的熱(re)伸長，從而減小管(guan)(guan)(guan)壁(bi)的應力(li)和作用(yong)在(zai)(zai)閥件或支架結構上的作用(yong)力(li)。