膨脹(zhang)節習慣上(shang)(shang)也叫(jiao)補(bu)償(chang)器，或(huo)伸縮節。由構(gou)(gou)成其工作主體(ti)(ti)的(de)(de)波紋管(guan)(guan)(guan)(一種(zhong)彈性(xing)元件(jian))和(he)端管(guan)(guan)(guan)、支(zhi)架、法蘭、導管(guan)(guan)(guan)等附件(jian)組成。 膨脹(zhang)節是為了補(bu)償(chang)因(yin)溫度差與機械振(zhen)動引起的(de)(de)附加(jia)應力，而設(she)置在(zai)容(rong)器殼體(ti)(ti)或(huo)管(guan)(guan)(guan)道(dao)上(shang)(shang)的(de)(de)一種(zhong)撓性(xing)結構(gou)(gou)。利用(yong)(yong)其工作主體(ti)(ti)波紋管(guan)(guan)(guan)的(de)(de)有效伸縮變(bian)形，以吸收管(guan)(guan)(guan)線、導管(guan)(guan)(guan)、容(rong)器等由熱(re)(re)(re)(re)脹(zhang)冷縮等原(yuan)因(yin)而產生(sheng)的(de)(de)尺寸變(bian)化，或(huo)補(bu)償(chang)管(guan)(guan)(guan)線、導管(guan)(guan)(guan)、容(rong)器等的(de)(de)軸向、橫向和(he)角(jiao)向位移。也可(ke)用(yong)(yong)于降噪(zao)減(jian)(jian)振(zhen)。供熱(re)(re)(re)(re)上(shang)(shang)，為了防止(zhi)供熱(re)(re)(re)(re)管(guan)(guan)(guan)道(dao)升溫時(shi)，由于熱(re)(re)(re)(re)伸長或(huo)溫度應力而引起管(guan)(guan)(guan)道(dao)變(bian)形或(huo)破壞，需要在(zai)管(guan)(guan)(guan)道(dao)上(shang)(shang)設(she)置補(bu)償(chang)器，以補(bu)償(chang)管(guan)(guan)(guan)道(dao)的(de)(de)熱(re)(re)(re)(re)伸長，從而減(jian)(jian)小管(guan)(guan)(guan)壁(bi)的(de)(de)應力和(he)作用(yong)(yong)在(zai)閥件(jian)或(huo)支(zhi)架結構(gou)(gou)上(shang)(shang)的(de)(de)作用(yong)(yong)力。