膨脹(zhang)節習慣上也叫(jiao)補(bu)(bu)償(chang)器，或伸(shen)縮節。由(you)構成其工作主體(ti)的(de)(de)(de)波(bo)紋管(guan)(guan)(guan)(guan)(一種(zhong)(zhong)彈性元件(jian))和端管(guan)(guan)(guan)(guan)、支架、法蘭、導(dao)管(guan)(guan)(guan)(guan)等附(fu)件(jian)組成。 膨脹(zhang)節是(shi)為了補(bu)(bu)償(chang)因(yin)溫度差與機械振(zhen)動(dong)引(yin)起的(de)(de)(de)附(fu)加應(ying)力(li)(li)，而(er)設置(zhi)在容(rong)器殼體(ti)或管(guan)(guan)(guan)(guan)道(dao)上的(de)(de)(de)一種(zhong)(zhong)撓性結構。利用(yong)其工作主體(ti)波(bo)紋管(guan)(guan)(guan)(guan)的(de)(de)(de)有效伸(shen)縮變(bian)形，以(yi)吸收(shou)管(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器等由(you)熱(re)(re)(re)脹(zhang)冷(leng)縮等原因(yin)而(er)產(chan)生的(de)(de)(de)尺寸變(bian)化，或補(bu)(bu)償(chang)管(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)、容(rong)器等的(de)(de)(de)軸(zhou)向(xiang)、橫向(xiang)和角向(xiang)位移。也可用(yong)于降噪減(jian)振(zhen)。供熱(re)(re)(re)上，為了防止供熱(re)(re)(re)管(guan)(guan)(guan)(guan)道(dao)升溫時，由(you)于熱(re)(re)(re)伸(shen)長或溫度應(ying)力(li)(li)而(er)引(yin)起管(guan)(guan)(guan)(guan)道(dao)變(bian)形或破(po)壞，需要在管(guan)(guan)(guan)(guan)道(dao)上設置(zhi)補(bu)(bu)償(chang)器，以(yi)補(bu)(bu)償(chang)管(guan)(guan)(guan)(guan)道(dao)的(de)(de)(de)熱(re)(re)(re)伸(shen)長，從而(er)減(jian)小(xiao)管(guan)(guan)(guan)(guan)壁的(de)(de)(de)應(ying)力(li)(li)和作用(yong)在閥(fa)件(jian)或支架結構上的(de)(de)(de)作用(yong)力(li)(li)。