膨脹節(jie)習慣上也叫(jiao)補(bu)(bu)償(chang)器，或(huo)伸(shen)縮(suo)節(jie)。由(you)(you)構成其工(gong)作(zuo)主(zhu)體(ti)的(de)(de)(de)波紋(wen)管(guan)(guan)(guan)(guan)(一種(zhong)(zhong)彈性(xing)元件(jian)(jian))和(he)端管(guan)(guan)(guan)(guan)、支(zhi)架、法(fa)蘭、導(dao)管(guan)(guan)(guan)(guan)等(deng)附件(jian)(jian)組成。 膨脹節(jie)是為了(le)(le)補(bu)(bu)償(chang)因(yin)溫(wen)(wen)度(du)差與(yu)機械振動引起的(de)(de)(de)附加應(ying)力(li)，而設置在(zai)容(rong)器殼(ke)體(ti)或(huo)管(guan)(guan)(guan)(guan)道(dao)上的(de)(de)(de)一種(zhong)(zhong)撓性(xing)結構。利用(yong)其工(gong)作(zuo)主(zhu)體(ti)波紋(wen)管(guan)(guan)(guan)(guan)的(de)(de)(de)有效伸(shen)縮(suo)變形，以吸收(shou)管(guan)(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器等(deng)由(you)(you)熱脹冷縮(suo)等(deng)原因(yin)而產生的(de)(de)(de)尺寸變化(hua)，或(huo)補(bu)(bu)償(chang)管(guan)(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器等(deng)的(de)(de)(de)軸向、橫向和(he)角向位移。也可(ke)用(yong)于降噪減振。供熱上，為了(le)(le)防止(zhi)供熱管(guan)(guan)(guan)(guan)道(dao)升溫(wen)(wen)時(shi)，由(you)(you)于熱伸(shen)長或(huo)溫(wen)(wen)度(du)應(ying)力(li)而引起管(guan)(guan)(guan)(guan)道(dao)變形或(huo)破(po)壞(huai)，需要在(zai)管(guan)(guan)(guan)(guan)道(dao)上設置補(bu)(bu)償(chang)器，以補(bu)(bu)償(chang)管(guan)(guan)(guan)(guan)道(dao)的(de)(de)(de)熱伸(shen)長，從而減小(xiao)管(guan)(guan)(guan)(guan)壁(bi)的(de)(de)(de)應(ying)力(li)和(he)作(zuo)用(yong)在(zai)閥(fa)件(jian)(jian)或(huo)支(zhi)架結構上的(de)(de)(de)作(zuo)用(yong)力(li)。