補(bu)償器(qi)(qi)習慣上(shang)也叫膨脹節，或伸(shen)(shen)縮節。由構(gou)成其工作主(zhu)體的(de)(de)波(bo)紋(wen)(wen)管(guan)(guan)(guan)(guan)（一(yi)種彈性元件(jian)(jian)）和端管(guan)(guan)(guan)(guan)、支(zhi)(zhi)架、法蘭、導管(guan)(guan)(guan)(guan)等(deng)附件(jian)(jian)組成。 屬于(yu)一(yi)種補(bu)償元件(jian)(jian)。利用(yong)(yong)其工作主(zhu)體波(bo)紋(wen)(wen)管(guan)(guan)(guan)(guan)的(de)(de)有效伸(shen)(shen)縮變形，以(yi)吸收管(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)等(deng)由熱(re)脹冷縮等(deng)原因而產生的(de)(de)尺寸變化(hua)，或補(bu)償管(guan)(guan)(guan)(guan)線(xian)、導管(guan)(guan)(guan)(guan)、容(rong)器(qi)(qi)等(deng)的(de)(de)軸向、橫向和角向位移。也可用(yong)(yong)于(yu)降(jiang)噪減振。在(zai)現代(dai)工業(ye)中用(yong)(yong)途廣泛。供熱(re)上(shang)，為了防止(zhi)供熱(re)管(guan)(guan)(guan)(guan)道(dao)升溫時，由于(yu)熱(re)伸(shen)(shen)長或溫度應(ying)力(li)而引起管(guan)(guan)(guan)(guan)道(dao)變形或破(po)壞(huai)，需要(yao)在(zai)管(guan)(guan)(guan)(guan)道(dao)上(shang)設置補(bu)償器(qi)(qi)，以(yi)補(bu)償管(guan)(guan)(guan)(guan)道(dao)的(de)(de)熱(re)伸(shen)(shen)長，從而減小管(guan)(guan)(guan)(guan)壁(bi)的(de)(de)應(ying)力(li)和作用(yong)(yong)在(zai)閥件(jian)(jian)或支(zhi)(zhi)架結構(gou)上(shang)的(de)(de)作用(yong)(yong)力(li)。