補(bu)償器(qi)習慣上也叫膨脹節(jie)，或伸縮節(jie)。由構成其(qi)(qi)工(gong)作主(zhu)(zhu)體的(de)(de)波紋(wen)管(guan)(guan)(guan)(guan)（一種彈性元(yuan)(yuan)件(jian)）和(he)端管(guan)(guan)(guan)(guan)、支架、法蘭、導(dao)管(guan)(guan)(guan)(guan)等(deng)附件(jian)組成。 屬于一種補(bu)償元(yuan)(yuan)件(jian)。利(li)用(yong)(yong)其(qi)(qi)工(gong)作主(zhu)(zhu)體波紋(wen)管(guan)(guan)(guan)(guan)的(de)(de)有效伸縮變(bian)形(xing)，以吸收(shou)管(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)、容器(qi)等(deng)由熱脹冷(leng)縮等(deng)原因而(er)產(chan)生的(de)(de)尺(chi)寸變(bian)化(hua)，或補(bu)償管(guan)(guan)(guan)(guan)線、導(dao)管(guan)(guan)(guan)(guan)、容器(qi)等(deng)的(de)(de)軸向(xiang)、橫向(xiang)和(he)角(jiao)向(xiang)位移。也可(ke)用(yong)(yong)于降噪減振。在現代工(gong)業中用(yong)(yong)途廣泛。供熱上，為(wei)了防止供熱管(guan)(guan)(guan)(guan)道升溫時，由于熱伸長(chang)或溫度應力而(er)引起管(guan)(guan)(guan)(guan)道變(bian)形(xing)或破壞，需要在管(guan)(guan)(guan)(guan)道上設(she)置補(bu)償器(qi)，以補(bu)償管(guan)(guan)(guan)(guan)道的(de)(de)熱伸長(chang)，從而(er)減小管(guan)(guan)(guan)(guan)壁的(de)(de)應力和(he)作用(yong)(yong)在閥件(jian)或支架結構上的(de)(de)作用(yong)(yong)力。