膨脹節(jie)(jie)習慣上(shang)也叫(jiao)補(bu)償(chang)器(qi)(qi)(qi)，或伸(shen)(shen)(shen)縮節(jie)(jie)。由構成(cheng)其工作主體(ti)的(de)波紋(wen)管(guan)(guan)(guan)(一種(zhong)彈性(xing)(xing)元件(jian))和(he)端管(guan)(guan)(guan)、支架、法(fa)蘭、導(dao)(dao)管(guan)(guan)(guan)等附(fu)件(jian)組成(cheng)。 膨脹節(jie)(jie)是為(wei)了(le)補(bu)償(chang)因(yin)溫度差與(yu)機械振動引起(qi)的(de)附(fu)加應力(li)(li)，而(er)設置在容(rong)(rong)器(qi)(qi)(qi)殼體(ti)或管(guan)(guan)(guan)道(dao)上(shang)的(de)一種(zhong)撓性(xing)(xing)結(jie)構。利(li)用(yong)(yong)其工作主體(ti)波紋(wen)管(guan)(guan)(guan)的(de)有(you)效伸(shen)(shen)(shen)縮變(bian)形(xing)，以吸收管(guan)(guan)(guan)線、導(dao)(dao)管(guan)(guan)(guan)、容(rong)(rong)器(qi)(qi)(qi)等由熱(re)(re)脹冷(leng)縮等原因(yin)而(er)產生的(de)尺寸(cun)變(bian)化，或補(bu)償(chang)管(guan)(guan)(guan)線、導(dao)(dao)管(guan)(guan)(guan)、容(rong)(rong)器(qi)(qi)(qi)等的(de)軸向(xiang)、橫(heng)向(xiang)和(he)角向(xiang)位移。也可用(yong)(yong)于(yu)(yu)降噪減振。供(gong)熱(re)(re)上(shang)，為(wei)了(le)防(fang)止供(gong)熱(re)(re)管(guan)(guan)(guan)道(dao)升溫時，由于(yu)(yu)熱(re)(re)伸(shen)(shen)(shen)長或溫度應力(li)(li)而(er)引起(qi)管(guan)(guan)(guan)道(dao)變(bian)形(xing)或破壞，需(xu)要在管(guan)(guan)(guan)道(dao)上(shang)設置補(bu)償(chang)器(qi)(qi)(qi)，以補(bu)償(chang)管(guan)(guan)(guan)道(dao)的(de)熱(re)(re)伸(shen)(shen)(shen)長，從(cong)而(er)減小管(guan)(guan)(guan)壁的(de)應力(li)(li)和(he)作用(yong)(yong)在閥件(jian)或支架結(jie)構上(shang)的(de)作用(yong)(yong)力(li)(li)。