膨脹節(jie)習慣上也(ye)叫補(bu)償(chang)器，或伸(shen)(shen)縮節(jie)。由(you)(you)構成其工作主體(ti)的波紋管(guan)(guan)(guan)(guan)(一(yi)種(zhong)彈性元件(jian))和端管(guan)(guan)(guan)(guan)、支(zhi)架、法蘭、導管(guan)(guan)(guan)(guan)等(deng)(deng)附(fu)件(jian)組成。 膨脹節(jie)是為了補(bu)償(chang)因(yin)溫(wen)(wen)度(du)差與機械振動引(yin)起(qi)的附(fu)加應力，而(er)(er)設置(zhi)(zhi)在容(rong)器殼體(ti)或管(guan)(guan)(guan)(guan)道上的一(yi)種(zhong)撓性結構。利用(yong)其工作主體(ti)波紋管(guan)(guan)(guan)(guan)的有效(xiao)伸(shen)(shen)縮變形，以吸收管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等(deng)(deng)由(you)(you)熱(re)脹冷縮等(deng)(deng)原因(yin)而(er)(er)產生的尺寸變化，或補(bu)償(chang)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等(deng)(deng)的軸向、橫向和角(jiao)向位移。也(ye)可用(yong)于(yu)(yu)降噪(zao)減振。供熱(re)上，為了防止(zhi)供熱(re)管(guan)(guan)(guan)(guan)道升溫(wen)(wen)時(shi)，由(you)(you)于(yu)(yu)熱(re)伸(shen)(shen)長(chang)或溫(wen)(wen)度(du)應力而(er)(er)引(yin)起(qi)管(guan)(guan)(guan)(guan)道變形或破壞，需要在管(guan)(guan)(guan)(guan)道上設置(zhi)(zhi)補(bu)償(chang)器，以補(bu)償(chang)管(guan)(guan)(guan)(guan)道的熱(re)伸(shen)(shen)長(chang)，從而(er)(er)減小(xiao)管(guan)(guan)(guan)(guan)壁的應力和作用(yong)在閥件(jian)或支(zhi)架結構上的作用(yong)力。