膨脹節(jie)習慣上也(ye)叫補償(chang)器(qi)(qi)(qi)，或伸(shen)縮節(jie)。由構成其工(gong)作主體的(de)(de)(de)(de)波(bo)(bo)紋(wen)管(guan)(guan)(guan)(一種(zhong)彈性(xing)元件(jian))和(he)端管(guan)(guan)(guan)、支(zhi)架(jia)、法蘭、導(dao)管(guan)(guan)(guan)等附件(jian)組成。 膨脹節(jie)是為(wei)了補償(chang)因溫(wen)度差與機械振(zhen)動引(yin)起的(de)(de)(de)(de)附加應力，而設置在(zai)容(rong)器(qi)(qi)(qi)殼(ke)體或管(guan)(guan)(guan)道(dao)上的(de)(de)(de)(de)一種(zhong)撓性(xing)結構。利用(yong)其工(gong)作主體波(bo)(bo)紋(wen)管(guan)(guan)(guan)的(de)(de)(de)(de)有效伸(shen)縮變(bian)(bian)形，以(yi)吸收管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)(qi)(qi)等由熱(re)脹冷(leng)縮等原因而產生的(de)(de)(de)(de)尺寸變(bian)(bian)化，或補償(chang)管(guan)(guan)(guan)線(xian)、導(dao)管(guan)(guan)(guan)、容(rong)器(qi)(qi)(qi)等的(de)(de)(de)(de)軸向、橫(heng)向和(he)角向位移。也(ye)可用(yong)于降(jiang)噪減(jian)振(zhen)。供熱(re)上，為(wei)了防止供熱(re)管(guan)(guan)(guan)道(dao)升溫(wen)時，由于熱(re)伸(shen)長或溫(wen)度應力而引(yin)起管(guan)(guan)(guan)道(dao)變(bian)(bian)形或破壞，需要在(zai)管(guan)(guan)(guan)道(dao)上設置補償(chang)器(qi)(qi)(qi)，以(yi)補償(chang)管(guan)(guan)(guan)道(dao)的(de)(de)(de)(de)熱(re)伸(shen)長，從而減(jian)小管(guan)(guan)(guan)壁的(de)(de)(de)(de)應力和(he)作用(yong)在(zai)閥(fa)件(jian)或支(zhi)架(jia)結構上的(de)(de)(de)(de)作用(yong)力。