膨脹節(jie)習慣上(shang)也叫補(bu)(bu)(bu)償(chang)(chang)器(qi)，或(huo)(huo)(huo)(huo)伸縮節(jie)。由構(gou)成其工(gong)作主(zhu)體的波紋管(guan)(guan)(guan)(guan)(一(yi)種彈性元件(jian))和端管(guan)(guan)(guan)(guan)、支架(jia)、法蘭、導(dao)管(guan)(guan)(guan)(guan)等附件(jian)組成。 膨脹節(jie)是(shi)為了(le)補(bu)(bu)(bu)償(chang)(chang)因溫(wen)(wen)度差(cha)與機(ji)械振動引(yin)起的附加應力(li)，而設置在(zai)(zai)容(rong)器(qi)殼體或(huo)(huo)(huo)(huo)管(guan)(guan)(guan)(guan)道(dao)(dao)上(shang)的一(yi)種撓性結構(gou)。利用(yong)其工(gong)作主(zhu)體波紋管(guan)(guan)(guan)(guan)的有(you)效伸縮變(bian)形，以(yi)吸收(shou)管(guan)(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器(qi)等由熱(re)脹冷縮等原因而產(chan)生(sheng)的尺寸變(bian)化，或(huo)(huo)(huo)(huo)補(bu)(bu)(bu)償(chang)(chang)管(guan)(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器(qi)等的軸向、橫向和角向位移(yi)。也可用(yong)于降(jiang)噪(zao)減振。供(gong)熱(re)上(shang)，為了(le)防止供(gong)熱(re)管(guan)(guan)(guan)(guan)道(dao)(dao)升溫(wen)(wen)時(shi)，由于熱(re)伸長或(huo)(huo)(huo)(huo)溫(wen)(wen)度應力(li)而引(yin)起管(guan)(guan)(guan)(guan)道(dao)(dao)變(bian)形或(huo)(huo)(huo)(huo)破壞(huai)，需要在(zai)(zai)管(guan)(guan)(guan)(guan)道(dao)(dao)上(shang)設置補(bu)(bu)(bu)償(chang)(chang)器(qi)，以(yi)補(bu)(bu)(bu)償(chang)(chang)管(guan)(guan)(guan)(guan)道(dao)(dao)的熱(re)伸長，從而減小管(guan)(guan)(guan)(guan)壁的應力(li)和作用(yong)在(zai)(zai)閥件(jian)或(huo)(huo)(huo)(huo)支架(jia)結構(gou)上(shang)的作用(yong)力(li)。