補(bu)償(chang)器(qi)(qi)習慣上(shang)也叫膨脹節，或伸縮節。由(you)構成(cheng)其(qi)工作(zuo)(zuo)主體的波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)（一種彈性元(yuan)件(jian)）和端管(guan)(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)(guan)等附件(jian)組成(cheng)。 屬于一種補(bu)償(chang)元(yuan)件(jian)。利用(yong)(yong)其(qi)工作(zuo)(zuo)主體波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)的有效伸縮變形(xing)，以(yi)吸收管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器(qi)(qi)等由(you)熱(re)(re)脹冷(leng)縮等原(yuan)因(yin)而(er)產生的尺寸(cun)變化，或補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器(qi)(qi)等的軸(zhou)向(xiang)、橫(heng)向(xiang)和角向(xiang)位移。也可用(yong)(yong)于降噪減振(zhen)。在現代工業中用(yong)(yong)途(tu)廣(guang)泛(fan)。供熱(re)(re)上(shang)，為了防止供熱(re)(re)管(guan)(guan)(guan)(guan)(guan)道(dao)升溫時(shi)，由(you)于熱(re)(re)伸長或溫度應力而(er)引起管(guan)(guan)(guan)(guan)(guan)道(dao)變形(xing)或破壞，需(xu)要(yao)在管(guan)(guan)(guan)(guan)(guan)道(dao)上(shang)設置補(bu)償(chang)器(qi)(qi)，以(yi)補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)道(dao)的熱(re)(re)伸長，從而(er)減小管(guan)(guan)(guan)(guan)(guan)壁的應力和作(zuo)(zuo)用(yong)(yong)在閥件(jian)或支架結構上(shang)的作(zuo)(zuo)用(yong)(yong)力。