焊接在管(guan)(guan)端(duan)或裝(zhuang)在管(guan)(guan)端(duan)外(wai)螺(luo)紋(wen)上以(yi)蓋堵管(guan)(guan)子的管(guan)(guan)件。用(yong)(yong)來封閉管(guan)(guan)路,作用(yong)(yong)與管(guan)(guan)堵相同 塑料管(guan)(guan)帽(mao)是采用(yong)(yong)塑料為主要原料加工而(er)成(cheng)管(guan)(guan)帽(mao)