Sentinel 7109's Superheater Assembled

The previous superheater article showed it passing its hydraulic test. Now it has been reassembled with the boiler's top plate at J R Goold Vintage Steam Restorations Ltd and it's as good as ready to fit to the boiler.

Superheater and Boiler assembly drawing

The superheater consists of four coils of tubing sitting in the top of the boiler supported by the top plate. The top plate then sits on top of the boiler inside the outer shell casing and is clamped down in six places.

Plan view of the superheater in place

Wet steam feeds the superheater inlet via a one to four-way manifold (elbow); the superheater outlet then feeds the stop valve and regulator assembly.

View through the top plate chimney apertures
The central support 'dish' is under construction

Four holes are provided for cleaning out with a steam lance. Each has a 'bung' to close it off when not in use. The bungs had become stuck fast due to corrosion and needed to be removed forcefully! As a result, new bosses had to be welded in place and tapped for the bungs. The bung's thread doesn't look too good and a new bung will be required. Fortunately this is an off-the-shelf item with a one inch BSP thread or thereabouts.

Reconstructed clean-out hole

Assembled top plate and superheater

Having said above that 'it's as good as ready to fit to the boiler', I have one hesitation; the central support 'dish'.

The support 'Dish'

For this to be effective, (you guessed) the dish has to be a larger diameter than the inner ring of the superheater. Thus it's not a bad idea to include the dish in the assembly before putting it all into the boiler as the dish won't fit through the inner ring from above afterwards!