膨脹節(jie)習慣上(shang)也叫補(bu)償器(qi)，或(huo)(huo)伸(shen)(shen)縮節(jie)。由構成其(qi)工作(zuo)主體的(de)波(bo)紋管(guan)(guan)(guan)(guan)(guan)(guan)(一(yi)(yi)種(zhong)(zhong)彈(dan)性(xing)元件(jian))和(he)端管(guan)(guan)(guan)(guan)(guan)(guan)、支架(jia)、法蘭(lan)、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)等附件(jian)組成。 膨脹節(jie)是為(wei)了(le)補(bu)償因溫(wen)度(du)(du)差(cha)與機械振動(dong)引(yin)(yin)起的(de)附加應(ying)力，而設置在(zai)容(rong)器(qi)殼體或(huo)(huo)管(guan)(guan)(guan)(guan)(guan)(guan)道上(shang)的(de)一(yi)(yi)種(zhong)(zhong)撓性(xing)結(jie)構。利用其(qi)工作(zuo)主體波(bo)紋管(guan)(guan)(guan)(guan)(guan)(guan)的(de)有效伸(shen)(shen)縮變(bian)形，以吸(xi)收管(guan)(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等由熱(re)脹冷縮等原因而產生(sheng)的(de)尺(chi)寸(cun)變(bian)化，或(huo)(huo)補(bu)償管(guan)(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等的(de)軸(zhou)向(xiang)、橫向(xiang)和(he)角向(xiang)位移。也可(ke)用于(yu)(yu)降(jiang)噪減振。供熱(re)上(shang)，為(wei)了(le)防止供熱(re)管(guan)(guan)(guan)(guan)(guan)(guan)道升溫(wen)時，由于(yu)(yu)熱(re)伸(shen)(shen)長或(huo)(huo)溫(wen)度(du)(du)應(ying)力而引(yin)(yin)起管(guan)(guan)(guan)(guan)(guan)(guan)道變(bian)形或(huo)(huo)破壞(huai)，需要在(zai)管(guan)(guan)(guan)(guan)(guan)(guan)道上(shang)設置補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)(guan)(guan)(guan)道的(de)熱(re)伸(shen)(shen)長，從而減小管(guan)(guan)(guan)(guan)(guan)(guan)壁的(de)應(ying)力和(he)作(zuo)用在(zai)閥件(jian)或(huo)(huo)支架(jia)結(jie)構上(shang)的(de)作(zuo)用力。