A.Allows passage of water but prevents the passage of steam
B.Allows passage of air but prevents passage of steam
C.Allows passage of the flue gases but prevents flow of steam
D.None of the above
A.Allows passage of water but prevents the passage of steam
B.Allows passage of air but prevents passage of steam
C.Allows passage of the flue gases but prevents flow of steam
D.None of the above