膨脹(zhang)(zhang)節(jie)習(xi)慣上(shang)(shang)也(ye)叫補(bu)償器(qi)，或伸(shen)縮(suo)節(jie)。由構成(cheng)其工作主體(ti)(ti)的(de)波紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)(一(yi)種(zhong)彈(dan)性元件)和(he)(he)端管(guan)(guan)(guan)(guan)(guan)(guan)(guan)、支(zhi)架(jia)(jia)、法蘭、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)等(deng)附(fu)件組成(cheng)。 膨脹(zhang)(zhang)節(jie)是為了補(bu)償因溫度(du)差與(yu)機(ji)械振動(dong)引(yin)起的(de)附(fu)加(jia)應力(li)，而(er)設置(zhi)在(zai)容(rong)器(qi)殼體(ti)(ti)或管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道上(shang)(shang)的(de)一(yi)種(zhong)撓性結構。利用(yong)(yong)其工作主體(ti)(ti)波紋管(guan)(guan)(guan)(guan)(guan)(guan)(guan)的(de)有效伸(shen)縮(suo)變(bian)形，以吸收管(guan)(guan)(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等(deng)由熱(re)脹(zhang)(zhang)冷縮(suo)等(deng)原(yuan)因而(er)產(chan)生(sheng)的(de)尺寸變(bian)化(hua)，或補(bu)償管(guan)(guan)(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)、容(rong)器(qi)等(deng)的(de)軸向、橫向和(he)(he)角(jiao)向位(wei)移。也(ye)可用(yong)(yong)于降噪減振。供(gong)熱(re)上(shang)(shang)，為了防止(zhi)供(gong)熱(re)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道升溫時(shi)，由于熱(re)伸(shen)長或溫度(du)應力(li)而(er)引(yin)起管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道變(bian)形或破壞，需要在(zai)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道上(shang)(shang)設置(zhi)補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)(guan)(guan)(guan)(guan)道的(de)熱(re)伸(shen)長，從(cong)而(er)減小(xiao)管(guan)(guan)(guan)(guan)(guan)(guan)(guan)壁(bi)的(de)應力(li)和(he)(he)作用(yong)(yong)在(zai)閥件或支(zhi)架(jia)(jia)結構上(shang)(shang)的(de)作用(yong)(yong)力(li)。