補(bu)償器(qi)習(xi)慣上(shang)也叫膨脹節，或(huo)伸縮節。由構成(cheng)其(qi)工作主體的(de)波紋(wen)管(guan)(guan)(guan)(guan)(guan)（一種彈性(xing)元件(jian)）和端(duan)管(guan)(guan)(guan)(guan)(guan)、支架(jia)、法蘭、導管(guan)(guan)(guan)(guan)(guan)等附件(jian)組成(cheng)。 屬于一種補(bu)償元件(jian)。利用(yong)其(qi)工作主體波紋(wen)管(guan)(guan)(guan)(guan)(guan)的(de)有(you)效伸縮變(bian)形，以吸收(shou)管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等由熱(re)脹冷縮等原因而(er)(er)產生的(de)尺寸(cun)變(bian)化，或(huo)補(bu)償管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等的(de)軸向(xiang)、橫向(xiang)和角向(xiang)位移。也可用(yong)于降噪減(jian)振。在現代工業中用(yong)途廣泛(fan)。供熱(re)上(shang)，為了防止供熱(re)管(guan)(guan)(guan)(guan)(guan)道升(sheng)溫時，由于熱(re)伸長或(huo)溫度應力而(er)(er)引起(qi)管(guan)(guan)(guan)(guan)(guan)道變(bian)形或(huo)破壞，需要在管(guan)(guan)(guan)(guan)(guan)道上(shang)設置補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)(guan)(guan)道的(de)熱(re)伸長，從而(er)(er)減(jian)小(xiao)管(guan)(guan)(guan)(guan)(guan)壁的(de)應力和作用(yong)在閥件(jian)或(huo)支架(jia)結構上(shang)的(de)作用(yong)力。