膨脹節(jie)習慣上(shang)也(ye)叫補(bu)償(chang)(chang)器(qi)，或(huo)(huo)伸(shen)(shen)縮(suo)節(jie)。由構成(cheng)其工作主(zhu)(zhu)體(ti)的波(bo)紋(wen)管(guan)(guan)(guan)(一種彈性(xing)元件(jian))和(he)端管(guan)(guan)(guan)、支架、法蘭、導(dao)管(guan)(guan)(guan)等(deng)附件(jian)組成(cheng)。 膨脹節(jie)是為了(le)(le)補(bu)償(chang)(chang)因(yin)溫(wen)度(du)差與機(ji)械振動引起的附加應(ying)力(li)，而設置在(zai)容(rong)(rong)器(qi)殼體(ti)或(huo)(huo)管(guan)(guan)(guan)道(dao)上(shang)的一種撓性(xing)結(jie)構。利用(yong)其工作主(zhu)(zhu)體(ti)波(bo)紋(wen)管(guan)(guan)(guan)的有效(xiao)伸(shen)(shen)縮(suo)變(bian)(bian)形(xing)，以(yi)吸收管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)(rong)器(qi)等(deng)由熱(re)(re)(re)脹冷縮(suo)等(deng)原因(yin)而產生(sheng)的尺(chi)寸變(bian)(bian)化，或(huo)(huo)補(bu)償(chang)(chang)管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)(rong)器(qi)等(deng)的軸向、橫(heng)向和(he)角向位移。也(ye)可(ke)用(yong)于降噪(zao)減振。供(gong)熱(re)(re)(re)上(shang)，為了(le)(le)防止供(gong)熱(re)(re)(re)管(guan)(guan)(guan)道(dao)升溫(wen)時(shi)，由于熱(re)(re)(re)伸(shen)(shen)長或(huo)(huo)溫(wen)度(du)應(ying)力(li)而引起管(guan)(guan)(guan)道(dao)變(bian)(bian)形(xing)或(huo)(huo)破壞(huai)，需要在(zai)管(guan)(guan)(guan)道(dao)上(shang)設置補(bu)償(chang)(chang)器(qi)，以(yi)補(bu)償(chang)(chang)管(guan)(guan)(guan)道(dao)的熱(re)(re)(re)伸(shen)(shen)長，從(cong)而減小管(guan)(guan)(guan)壁的應(ying)力(li)和(he)作用(yong)在(zai)閥件(jian)或(huo)(huo)支架結(jie)構上(shang)的作用(yong)力(li)。