膨(peng)(peng)脹(zhang)(zhang)節(jie)習慣上也叫補(bu)償(chang)(chang)器，或伸縮(suo)節(jie)。由(you)(you)構(gou)成其工作(zuo)主(zhu)體的波紋管(guan)(guan)(guan)(guan)(一種彈性元件)和(he)端管(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)等附(fu)件組成。 膨(peng)(peng)脹(zhang)(zhang)節(jie)是為了(le)(le)補(bu)償(chang)(chang)因溫(wen)度差(cha)與(yu)機械(xie)振動引起(qi)的附(fu)加應力，而(er)設(she)置(zhi)(zhi)在(zai)容(rong)器殼體或管(guan)(guan)(guan)(guan)道(dao)上的一種撓性結構(gou)。利用(yong)(yong)(yong)其工作(zuo)主(zhu)體波紋管(guan)(guan)(guan)(guan)的有效伸縮(suo)變形(xing)，以吸收管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等由(you)(you)熱(re)脹(zhang)(zhang)冷縮(suo)等原因而(er)產(chan)生的尺寸變化，或補(bu)償(chang)(chang)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器等的軸向(xiang)、橫向(xiang)和(he)角(jiao)向(xiang)位(wei)移。也可用(yong)(yong)(yong)于(yu)降噪減振。供熱(re)上，為了(le)(le)防(fang)止供熱(re)管(guan)(guan)(guan)(guan)道(dao)升溫(wen)時，由(you)(you)于(yu)熱(re)伸長(chang)(chang)或溫(wen)度應力而(er)引起(qi)管(guan)(guan)(guan)(guan)道(dao)變形(xing)或破壞，需要在(zai)管(guan)(guan)(guan)(guan)道(dao)上設(she)置(zhi)(zhi)補(bu)償(chang)(chang)器，以補(bu)償(chang)(chang)管(guan)(guan)(guan)(guan)道(dao)的熱(re)伸長(chang)(chang)，從(cong)而(er)減小管(guan)(guan)(guan)(guan)壁的應力和(he)作(zuo)用(yong)(yong)(yong)在(zai)閥件或支架結構(gou)上的作(zuo)用(yong)(yong)(yong)力。