補(bu)償(chang)器(qi)習慣(guan)上也叫膨脹節，或(huo)伸(shen)(shen)縮(suo)節。由構(gou)成(cheng)其工(gong)(gong)作主體的波(bo)紋管(guan)(guan)（一(yi)種(zhong)彈性元(yuan)件）和(he)端(duan)管(guan)(guan)、支架、法蘭、導管(guan)(guan)等(deng)附件組成(cheng)。 屬于一(yi)種(zhong)補(bu)償(chang)元(yuan)件。利用(yong)(yong)其工(gong)(gong)作主體波(bo)紋管(guan)(guan)的有效伸(shen)(shen)縮(suo)變(bian)形，以(yi)吸收管(guan)(guan)線(xian)、導管(guan)(guan)、容(rong)器(qi)等(deng)由熱脹冷(leng)縮(suo)等(deng)原因而(er)產生的尺寸變(bian)化，或(huo)補(bu)償(chang)管(guan)(guan)線(xian)、導管(guan)(guan)、容(rong)器(qi)等(deng)的軸向、橫向和(he)角向位移。也可用(yong)(yong)于降噪減(jian)振。在現(xian)代工(gong)(gong)業(ye)中用(yong)(yong)途廣泛。供熱上，為了防(fang)止(zhi)供熱管(guan)(guan)道(dao)升溫時(shi)，由于熱伸(shen)(shen)長或(huo)溫度應力而(er)引起管(guan)(guan)道(dao)變(bian)形或(huo)破壞(huai)，需要(yao)在管(guan)(guan)道(dao)上設置補(bu)償(chang)器(qi)，以(yi)補(bu)償(chang)管(guan)(guan)道(dao)的熱伸(shen)(shen)長，從而(er)減(jian)小管(guan)(guan)壁(bi)的應力和(he)作用(yong)(yong)在閥件或(huo)支架結構(gou)上的作用(yong)(yong)力。