膨脹(zhang)(zhang)節(jie)習慣上(shang)也叫補(bu)(bu)償(chang)(chang)(chang)(chang)器(qi)，或(huo)伸縮節(jie)。由構(gou)成其(qi)工(gong)作(zuo)主(zhu)體的(de)(de)波紋管(guan)(guan)(guan)(guan)(一(yi)種彈性(xing)元件)和端(duan)管(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)等(deng)附件組成。 膨脹(zhang)(zhang)節(jie)是為(wei)了補(bu)(bu)償(chang)(chang)(chang)(chang)因溫(wen)(wen)度(du)(du)差與(yu)機械(xie)振動引起(qi)的(de)(de)附加(jia)應力，而(er)(er)(er)設(she)置在容(rong)(rong)(rong)器(qi)殼(ke)體或(huo)管(guan)(guan)(guan)(guan)道(dao)上(shang)的(de)(de)一(yi)種撓性(xing)結構(gou)。利用(yong)其(qi)工(gong)作(zuo)主(zhu)體波紋管(guan)(guan)(guan)(guan)的(de)(de)有效伸縮變(bian)(bian)(bian)形，以吸(xi)收管(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)、容(rong)(rong)(rong)器(qi)等(deng)由熱(re)脹(zhang)(zhang)冷縮等(deng)原因而(er)(er)(er)產生的(de)(de)尺寸變(bian)(bian)(bian)化(hua)，或(huo)補(bu)(bu)償(chang)(chang)(chang)(chang)管(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)、容(rong)(rong)(rong)器(qi)等(deng)的(de)(de)軸向(xiang)、橫向(xiang)和角向(xiang)位移(yi)。也可(ke)用(yong)于(yu)降(jiang)噪減振。供熱(re)上(shang)，為(wei)了防止供熱(re)管(guan)(guan)(guan)(guan)道(dao)升溫(wen)(wen)時，由于(yu)熱(re)伸長或(huo)溫(wen)(wen)度(du)(du)應力而(er)(er)(er)引起(qi)管(guan)(guan)(guan)(guan)道(dao)變(bian)(bian)(bian)形或(huo)破壞(huai)，需要(yao)在管(guan)(guan)(guan)(guan)道(dao)上(shang)設(she)置補(bu)(bu)償(chang)(chang)(chang)(chang)器(qi)，以補(bu)(bu)償(chang)(chang)(chang)(chang)管(guan)(guan)(guan)(guan)道(dao)的(de)(de)熱(re)伸長，從而(er)(er)(er)減小管(guan)(guan)(guan)(guan)壁的(de)(de)應力和作(zuo)用(yong)在閥件或(huo)支架結構(gou)上(shang)的(de)(de)作(zuo)用(yong)力。