膨脹節習慣上(shang)(shang)也(ye)叫補償器(qi)(qi)，或伸縮節。由(you)構成其工(gong)作(zuo)主(zhu)體的(de)(de)(de)波紋(wen)(wen)管(guan)(guan)(guan)(guan)(一種(zhong)彈性元件(jian))和端管(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)等(deng)附件(jian)組成。 膨脹節是(shi)為了補償因溫(wen)(wen)度差與(yu)機械(xie)振動引(yin)起的(de)(de)(de)附加(jia)應(ying)力，而(er)(er)設置在容(rong)器(qi)(qi)殼體或管(guan)(guan)(guan)(guan)道(dao)上(shang)(shang)的(de)(de)(de)一種(zhong)撓性結構。利用(yong)其工(gong)作(zuo)主(zhu)體波紋(wen)(wen)管(guan)(guan)(guan)(guan)的(de)(de)(de)有效(xiao)伸縮變形(xing)，以(yi)吸收(shou)管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)等(deng)由(you)熱(re)脹冷(leng)縮等(deng)原(yuan)因而(er)(er)產生的(de)(de)(de)尺寸變化，或補償管(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)等(deng)的(de)(de)(de)軸向、橫(heng)向和角向位移。也(ye)可用(yong)于降噪減振。供熱(re)上(shang)(shang)，為了防止供熱(re)管(guan)(guan)(guan)(guan)道(dao)升溫(wen)(wen)時，由(you)于熱(re)伸長或溫(wen)(wen)度應(ying)力而(er)(er)引(yin)起管(guan)(guan)(guan)(guan)道(dao)變形(xing)或破(po)壞，需要(yao)在管(guan)(guan)(guan)(guan)道(dao)上(shang)(shang)設置補償器(qi)(qi)，以(yi)補償管(guan)(guan)(guan)(guan)道(dao)的(de)(de)(de)熱(re)伸長，從而(er)(er)減小管(guan)(guan)(guan)(guan)壁(bi)的(de)(de)(de)應(ying)力和作(zuo)用(yong)在閥(fa)件(jian)或支架結構上(shang)(shang)的(de)(de)(de)作(zuo)用(yong)力。