Tubeplate

Such soot blowers often have movable jets so that the jet can be directed towards different parts of the tubeplate in turn.

The smokebox tubeplate is of the drum-head type, and there are 21 large flue tubes, 5⅛ in. dia. outside, and 157 small tubes, 1¾ in. dia. outside; length between tubeplates is 13 ft.