膨脹節習慣上(shang)(shang)也叫補(bu)償(chang)器(qi)，或伸縮節。由(you)構(gou)成其工作(zuo)(zuo)主體(ti)的(de)(de)(de)(de)波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)(一種彈(dan)性元件)和端管(guan)(guan)(guan)(guan)(guan)(guan)、支(zhi)架(jia)、法蘭、導管(guan)(guan)(guan)(guan)(guan)(guan)等附件組成。 膨脹節是為了(le)補(bu)償(chang)因(yin)溫(wen)度(du)(du)差(cha)與機(ji)械(xie)振(zhen)(zhen)動引起的(de)(de)(de)(de)附加應力，而(er)(er)設置(zhi)在(zai)容(rong)(rong)器(qi)殼體(ti)或管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)上(shang)(shang)的(de)(de)(de)(de)一種撓(nao)性結(jie)構(gou)。利用(yong)(yong)其工作(zuo)(zuo)主體(ti)波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)有效伸縮變(bian)形，以吸(xi)收管(guan)(guan)(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)(rong)器(qi)等由(you)熱脹冷縮等原因(yin)而(er)(er)產生的(de)(de)(de)(de)尺(chi)寸變(bian)化，或補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)(rong)器(qi)等的(de)(de)(de)(de)軸向(xiang)(xiang)、橫向(xiang)(xiang)和角向(xiang)(xiang)位移。也可(ke)用(yong)(yong)于降(jiang)噪減振(zhen)(zhen)。供熱上(shang)(shang)，為了(le)防止(zhi)供熱管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)升溫(wen)時，由(you)于熱伸長或溫(wen)度(du)(du)應力而(er)(er)引起管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)變(bian)形或破壞，需要在(zai)管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)上(shang)(shang)設置(zhi)補(bu)償(chang)器(qi)，以補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)(guan)道(dao)的(de)(de)(de)(de)熱伸長，從(cong)而(er)(er)減小管(guan)(guan)(guan)(guan)(guan)(guan)壁的(de)(de)(de)(de)應力和作(zuo)(zuo)用(yong)(yong)在(zai)閥件或支(zhi)架(jia)結(jie)構(gou)上(shang)(shang)的(de)(de)(de)(de)作(zuo)(zuo)用(yong)(yong)力。