膨脹節習(xi)慣上(shang)(shang)也(ye)叫補(bu)償(chang)器，或(huo)伸(shen)縮節。由構(gou)(gou)成其工(gong)作(zuo)主體(ti)的(de)波紋管(guan)(guan)(guan)(guan)(一種彈(dan)性元件(jian))和端管(guan)(guan)(guan)(guan)、支(zhi)架、法(fa)蘭、導管(guan)(guan)(guan)(guan)等附(fu)件(jian)組成。 膨脹節是為了(le)補(bu)償(chang)因(yin)溫(wen)度差與機械(xie)振動引起的(de)附(fu)加應力(li)(li)，而(er)(er)設置在(zai)容(rong)器殼(ke)體(ti)或(huo)管(guan)(guan)(guan)(guan)道(dao)(dao)上(shang)(shang)的(de)一種撓性結構(gou)(gou)。利用(yong)其工(gong)作(zuo)主體(ti)波紋管(guan)(guan)(guan)(guan)的(de)有(you)效伸(shen)縮變(bian)形(xing)，以吸收管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等由熱(re)脹冷(leng)縮等原因(yin)而(er)(er)產生的(de)尺寸變(bian)化，或(huo)補(bu)償(chang)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等的(de)軸向(xiang)、橫向(xiang)和角向(xiang)位移。也(ye)可用(yong)于降噪減振。供(gong)(gong)熱(re)上(shang)(shang)，為了(le)防止供(gong)(gong)熱(re)管(guan)(guan)(guan)(guan)道(dao)(dao)升(sheng)溫(wen)時(shi)，由于熱(re)伸(shen)長或(huo)溫(wen)度應力(li)(li)而(er)(er)引起管(guan)(guan)(guan)(guan)道(dao)(dao)變(bian)形(xing)或(huo)破壞，需(xu)要在(zai)管(guan)(guan)(guan)(guan)道(dao)(dao)上(shang)(shang)設置補(bu)償(chang)器，以補(bu)償(chang)管(guan)(guan)(guan)(guan)道(dao)(dao)的(de)熱(re)伸(shen)長，從而(er)(er)減小管(guan)(guan)(guan)(guan)壁的(de)應力(li)(li)和作(zuo)用(yong)在(zai)閥件(jian)或(huo)支(zhi)架結構(gou)(gou)上(shang)(shang)的(de)作(zuo)用(yong)力(li)(li)。