A.烟火管 B.炉膛 C.对流管束 D.集箱
A.60cm B.30cm C.40cm D.50cm
A.50mm B.100mm C.200mm D.300mm
A.封头 B.壳体 C.法兰 D.接管
A.2% B.3% C.4% D.5%
