補(bu)償器(qi)習(xi)慣上也叫膨脹節，或(huo)伸縮節。由(you)構(gou)成其工(gong)(gong)作主體的(de)(de)波(bo)紋管(guan)(guan)(guan)（一種彈性(xing)元件(jian)(jian)）和(he)(he)(he)端(duan)管(guan)(guan)(guan)、支架、法(fa)蘭、導(dao)管(guan)(guan)(guan)等附(fu)件(jian)(jian)組成。 屬于一種補(bu)償元件(jian)(jian)。利用(yong)其工(gong)(gong)作主體波(bo)紋管(guan)(guan)(guan)的(de)(de)有效伸縮變(bian)形，以吸收管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)等由(you)熱(re)(re)脹冷縮等原因而(er)(er)(er)產生的(de)(de)尺寸(cun)變(bian)化，或(huo)補(bu)償管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)等的(de)(de)軸向、橫向和(he)(he)(he)角向位移。也可用(yong)于降噪減(jian)振。在(zai)現代(dai)工(gong)(gong)業中用(yong)途廣(guang)泛。供熱(re)(re)上，為了防止供熱(re)(re)管(guan)(guan)(guan)道(dao)升溫時，由(you)于熱(re)(re)伸長或(huo)溫度應力(li)而(er)(er)(er)引起管(guan)(guan)(guan)道(dao)變(bian)形或(huo)破(po)壞，需要在(zai)管(guan)(guan)(guan)道(dao)上設置(zhi)補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)道(dao)的(de)(de)熱(re)(re)伸長，從而(er)(er)(er)減(jian)小管(guan)(guan)(guan)壁的(de)(de)應力(li)和(he)(he)(he)作用(yong)在(zai)閥件(jian)(jian)或(huo)支架結構(gou)上的(de)(de)作用(yong)力(li)。