補(bu)(bu)償(chang)器(qi)習慣上也叫膨脹節，或(huo)伸縮(suo)節。由構成其工(gong)作主體的波紋管(guan)(guan)(guan)（一種(zhong)彈性元(yuan)(yuan)件(jian)）和(he)端(duan)管(guan)(guan)(guan)、支(zhi)架、法(fa)蘭、導(dao)管(guan)(guan)(guan)等(deng)附件(jian)組成。 屬于一種(zhong)補(bu)(bu)償(chang)元(yuan)(yuan)件(jian)。利用(yong)其工(gong)作主體波紋管(guan)(guan)(guan)的有效伸縮(suo)變(bian)(bian)形(xing)，以吸收管(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)等(deng)由熱脹冷縮(suo)等(deng)原(yuan)因而產生(sheng)的尺寸變(bian)(bian)化，或(huo)補(bu)(bu)償(chang)管(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)等(deng)的軸(zhou)向(xiang)、橫向(xiang)和(he)角向(xiang)位移(yi)。也可用(yong)于降噪減振(zhen)。在(zai)現代工(gong)業中用(yong)途(tu)廣泛。供熱上，為了防(fang)止供熱管(guan)(guan)(guan)道(dao)升溫時(shi)，由于熱伸長(chang)(chang)或(huo)溫度應(ying)力(li)而引起管(guan)(guan)(guan)道(dao)變(bian)(bian)形(xing)或(huo)破壞，需要(yao)在(zai)管(guan)(guan)(guan)道(dao)上設(she)置補(bu)(bu)償(chang)器(qi)，以補(bu)(bu)償(chang)管(guan)(guan)(guan)道(dao)的熱伸長(chang)(chang)，從而減小管(guan)(guan)(guan)壁的應(ying)力(li)和(he)作用(yong)在(zai)閥件(jian)或(huo)支(zhi)架結構上的作用(yong)力(li)。