膨脹(zhang)(zhang)節習(xi)慣上(shang)也(ye)(ye)叫補(bu)償(chang)器(qi)(qi)(qi)，或(huo)伸縮節。由構(gou)成(cheng)其工作(zuo)主(zhu)體的(de)波(bo)紋(wen)管(guan)(guan)(guan)(guan)(一種彈性元件(jian))和端管(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)等(deng)附(fu)件(jian)組成(cheng)。 膨脹(zhang)(zhang)節是(shi)為了(le)補(bu)償(chang)因溫(wen)度差(cha)與機(ji)械(xie)振(zhen)(zhen)動引起(qi)的(de)附(fu)加應(ying)(ying)力，而(er)(er)設(she)置(zhi)在容(rong)器(qi)(qi)(qi)殼(ke)體或(huo)管(guan)(guan)(guan)(guan)道(dao)上(shang)的(de)一種撓(nao)性結構(gou)。利用(yong)(yong)其工作(zuo)主(zhu)體波(bo)紋(wen)管(guan)(guan)(guan)(guan)的(de)有效伸縮變形，以吸(xi)收(shou)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)(qi)等(deng)由熱(re)(re)脹(zhang)(zhang)冷(leng)縮等(deng)原因而(er)(er)產生的(de)尺寸變化(hua)，或(huo)補(bu)償(chang)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)(qi)等(deng)的(de)軸(zhou)向、橫向和角向位移。也(ye)(ye)可用(yong)(yong)于降噪減振(zhen)(zhen)。供熱(re)(re)上(shang)，為了(le)防止供熱(re)(re)管(guan)(guan)(guan)(guan)道(dao)升(sheng)溫(wen)時(shi)，由于熱(re)(re)伸長或(huo)溫(wen)度應(ying)(ying)力而(er)(er)引起(qi)管(guan)(guan)(guan)(guan)道(dao)變形或(huo)破壞，需要在管(guan)(guan)(guan)(guan)道(dao)上(shang)設(she)置(zhi)補(bu)償(chang)器(qi)(qi)(qi)，以補(bu)償(chang)管(guan)(guan)(guan)(guan)道(dao)的(de)熱(re)(re)伸長，從而(er)(er)減小管(guan)(guan)(guan)(guan)壁(bi)的(de)應(ying)(ying)力和作(zuo)用(yong)(yong)在閥(fa)件(jian)或(huo)支架結構(gou)上(shang)的(de)作(zuo)用(yong)(yong)力。