補償器(qi)習慣上(shang)也叫膨脹節，或(huo)伸縮(suo)節。由構成(cheng)其(qi)工(gong)作(zuo)主體(ti)(ti)的(de)波(bo)(bo)紋管(guan)(guan)(guan)(guan)(guan)（一種彈(dan)性(xing)元件(jian)(jian)）和端管(guan)(guan)(guan)(guan)(guan)、支(zhi)(zhi)架、法蘭、導管(guan)(guan)(guan)(guan)(guan)等(deng)附件(jian)(jian)組成(cheng)。 屬于(yu)一種補償元件(jian)(jian)。利用(yong)其(qi)工(gong)作(zuo)主體(ti)(ti)波(bo)(bo)紋管(guan)(guan)(guan)(guan)(guan)的(de)有效(xiao)伸縮(suo)變(bian)形，以(yi)吸收管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器(qi)等(deng)由熱脹冷縮(suo)等(deng)原因(yin)而產生的(de)尺寸變(bian)化，或(huo)補償管(guan)(guan)(guan)(guan)(guan)線、導管(guan)(guan)(guan)(guan)(guan)、容器(qi)等(deng)的(de)軸向、橫向和角向位移(yi)。也可(ke)用(yong)于(yu)降噪(zao)減振。在(zai)現代工(gong)業中(zhong)用(yong)途廣(guang)泛。供熱上(shang)，為了防止(zhi)供熱管(guan)(guan)(guan)(guan)(guan)道升(sheng)溫時，由于(yu)熱伸長(chang)或(huo)溫度(du)應力(li)而引起(qi)管(guan)(guan)(guan)(guan)(guan)道變(bian)形或(huo)破壞，需要在(zai)管(guan)(guan)(guan)(guan)(guan)道上(shang)設置(zhi)補償器(qi)，以(yi)補償管(guan)(guan)(guan)(guan)(guan)道的(de)熱伸長(chang)，從而減小管(guan)(guan)(guan)(guan)(guan)壁的(de)應力(li)和作(zuo)用(yong)在(zai)閥件(jian)(jian)或(huo)支(zhi)(zhi)架結構上(shang)的(de)作(zuo)用(yong)力(li)。