補(bu)償器(qi)習慣上(shang)也叫膨脹節，或伸(shen)(shen)縮節。由構成其工作(zuo)主體(ti)的波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)（一(yi)種(zhong)彈性元件(jian)(jian)）和(he)端(duan)管(guan)(guan)(guan)(guan)(guan)、支(zhi)架、法蘭、導(dao)管(guan)(guan)(guan)(guan)(guan)等(deng)附(fu)件(jian)(jian)組成。 屬于(yu)(yu)一(yi)種(zhong)補(bu)償元件(jian)(jian)。利用(yong)其工作(zuo)主體(ti)波(bo)紋(wen)管(guan)(guan)(guan)(guan)(guan)的有效伸(shen)(shen)縮變(bian)形(xing)，以吸收管(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)、容器(qi)等(deng)由熱脹冷縮等(deng)原(yuan)因而產(chan)生的尺寸變(bian)化，或補(bu)償管(guan)(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)(guan)、容器(qi)等(deng)的軸向(xiang)(xiang)、橫向(xiang)(xiang)和(he)角向(xiang)(xiang)位(wei)移(yi)。也可用(yong)于(yu)(yu)降噪減(jian)振。在(zai)現代工業中(zhong)用(yong)途廣(guang)泛。供(gong)熱上(shang)，為了防止(zhi)供(gong)熱管(guan)(guan)(guan)(guan)(guan)道升溫時，由于(yu)(yu)熱伸(shen)(shen)長(chang)或溫度應力而引(yin)起管(guan)(guan)(guan)(guan)(guan)道變(bian)形(xing)或破壞，需要(yao)在(zai)管(guan)(guan)(guan)(guan)(guan)道上(shang)設置補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)(guan)(guan)道的熱伸(shen)(shen)長(chang)，從而減(jian)小(xiao)管(guan)(guan)(guan)(guan)(guan)壁(bi)的應力和(he)作(zuo)用(yong)在(zai)閥件(jian)(jian)或支(zhi)架結構上(shang)的作(zuo)用(yong)力。