膨脹(zhang)節(jie)習慣上也叫(jiao)補償(chang)器，或(huo)伸(shen)(shen)縮節(jie)。由(you)(you)構(gou)成其工作主體(ti)的(de)(de)波(bo)紋管(guan)(guan)(guan)(一(yi)種(zhong)(zhong)彈(dan)性(xing)元件)和端管(guan)(guan)(guan)、支架、法蘭、導(dao)管(guan)(guan)(guan)等(deng)附(fu)件組成。 膨脹(zhang)節(jie)是為(wei)了(le)(le)補償(chang)因溫度差(cha)與機械振(zhen)動引起(qi)的(de)(de)附(fu)加(jia)應力(li)(li)，而設置(zhi)在(zai)容(rong)器殼(ke)體(ti)或(huo)管(guan)(guan)(guan)道(dao)上的(de)(de)一(yi)種(zhong)(zhong)撓性(xing)結(jie)構(gou)。利用(yong)(yong)其工作主體(ti)波(bo)紋管(guan)(guan)(guan)的(de)(de)有效伸(shen)(shen)縮變(bian)形(xing)，以(yi)吸收管(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)、容(rong)器等(deng)由(you)(you)熱(re)脹(zhang)冷縮等(deng)原因而產生(sheng)的(de)(de)尺寸變(bian)化(hua)，或(huo)補償(chang)管(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)、容(rong)器等(deng)的(de)(de)軸(zhou)向、橫(heng)向和角向位移。也可用(yong)(yong)于降噪減(jian)振(zhen)。供(gong)熱(re)上，為(wei)了(le)(le)防止供(gong)熱(re)管(guan)(guan)(guan)道(dao)升(sheng)溫時，由(you)(you)于熱(re)伸(shen)(shen)長或(huo)溫度應力(li)(li)而引起(qi)管(guan)(guan)(guan)道(dao)變(bian)形(xing)或(huo)破壞，需要在(zai)管(guan)(guan)(guan)道(dao)上設置(zhi)補償(chang)器，以(yi)補償(chang)管(guan)(guan)(guan)道(dao)的(de)(de)熱(re)伸(shen)(shen)長，從而減(jian)小管(guan)(guan)(guan)壁的(de)(de)應力(li)(li)和作用(yong)(yong)在(zai)閥件或(huo)支架結(jie)構(gou)上的(de)(de)作用(yong)(yong)力(li)(li)。