膨脹(zhang)節習慣上也(ye)叫補(bu)償(chang)器(qi)，或(huo)伸縮(suo)節。由(you)構成其(qi)工(gong)作主體(ti)的(de)(de)(de)(de)波(bo)紋管(guan)(guan)(guan)(一種(zhong)彈(dan)性元(yuan)件(jian)(jian)(jian))和端(duan)管(guan)(guan)(guan)、支(zhi)架、法蘭、導管(guan)(guan)(guan)等附件(jian)(jian)(jian)組成。 膨脹(zhang)節是為(wei)了補(bu)償(chang)因溫(wen)度(du)差與機械(xie)振動引起(qi)的(de)(de)(de)(de)附加應(ying)力，而(er)設置(zhi)在(zai)容(rong)器(qi)殼(ke)體(ti)或(huo)管(guan)(guan)(guan)道(dao)上的(de)(de)(de)(de)一種(zhong)撓性結(jie)構。利用其(qi)工(gong)作主體(ti)波(bo)紋管(guan)(guan)(guan)的(de)(de)(de)(de)有效伸縮(suo)變(bian)形(xing)，以吸(xi)收管(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)、容(rong)器(qi)等由(you)熱(re)(re)脹(zhang)冷(leng)縮(suo)等原(yuan)因而(er)產生的(de)(de)(de)(de)尺寸變(bian)化，或(huo)補(bu)償(chang)管(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)、容(rong)器(qi)等的(de)(de)(de)(de)軸向(xiang)、橫向(xiang)和角向(xiang)位移。也(ye)可(ke)用于降噪減(jian)振。供熱(re)(re)上，為(wei)了防止供熱(re)(re)管(guan)(guan)(guan)道(dao)升溫(wen)時，由(you)于熱(re)(re)伸長或(huo)溫(wen)度(du)應(ying)力而(er)引起(qi)管(guan)(guan)(guan)道(dao)變(bian)形(xing)或(huo)破壞，需要在(zai)管(guan)(guan)(guan)道(dao)上設置(zhi)補(bu)償(chang)器(qi)，以補(bu)償(chang)管(guan)(guan)(guan)道(dao)的(de)(de)(de)(de)熱(re)(re)伸長，從而(er)減(jian)小管(guan)(guan)(guan)壁的(de)(de)(de)(de)應(ying)力和作用在(zai)閥件(jian)(jian)(jian)或(huo)支(zhi)架結(jie)構上的(de)(de)(de)(de)作用力。