膨脹節習慣上也叫補(bu)償(chang)器，或伸(shen)(shen)縮節。由(you)構成其工作主體的(de)(de)波紋管(guan)(guan)(guan)(guan)(guan)(一種(zhong)彈性元件)和端管(guan)(guan)(guan)(guan)(guan)、支架、法蘭、導管(guan)(guan)(guan)(guan)(guan)等附件組成。 膨脹節是為(wei)(wei)了(le)補(bu)償(chang)因溫(wen)度差與機械振動引起(qi)的(de)(de)附加應力，而設置在(zai)容器殼體或管(guan)(guan)(guan)(guan)(guan)道上的(de)(de)一種(zhong)撓(nao)性結(jie)構。利(li)用(yong)其工作主體波紋管(guan)(guan)(guan)(guan)(guan)的(de)(de)有(you)效伸(shen)(shen)縮變形，以吸收管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器等由(you)熱脹冷縮等原因而產(chan)生的(de)(de)尺寸變化(hua)，或補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器等的(de)(de)軸(zhou)向(xiang)、橫(heng)向(xiang)和角(jiao)向(xiang)位移(yi)。也可用(yong)于降(jiang)噪減振。供(gong)熱上，為(wei)(wei)了(le)防(fang)止(zhi)供(gong)熱管(guan)(guan)(guan)(guan)(guan)道升溫(wen)時(shi)，由(you)于熱伸(shen)(shen)長或溫(wen)度應力而引起(qi)管(guan)(guan)(guan)(guan)(guan)道變形或破壞，需(xu)要在(zai)管(guan)(guan)(guan)(guan)(guan)道上設置補(bu)償(chang)器，以補(bu)償(chang)管(guan)(guan)(guan)(guan)(guan)道的(de)(de)熱伸(shen)(shen)長，從(cong)而減小管(guan)(guan)(guan)(guan)(guan)壁(bi)的(de)(de)應力和作用(yong)在(zai)閥(fa)件或支架結(jie)構上的(de)(de)作用(yong)力。