The King is fitted with a GWR No.9 boiler, a 250lbs per square inch pressure
vessel heated from a long and comparatively narrow firebox that sits between the
two main frames of the locomotive. A coal fire, vented from beneath the engine,
and fed with coal by the fireman, sends exhaust gases forward through the
tapered cylindrical boiler by a series of smoke tubes that pass through the
water space. The exhaust is then drawn up the chimney from the front smoke box
by the action of the blastpipe that exhausts the spent steam from the cylinders.
The pressurised water space extends around the firebox to maximise the
heating effect. This means that there are narrow spaces in the rear part of the
pressurised boiler within which huge forces are held in check by hundreds of
stays that pass through the outside wrapper of the firebox, through the
pressurised space, and into the inner wrapper. This is why in photos of the bare
boiler, there is a long smooth barrel, backed by an ugly irregular box punctured
by hundreds of bolts.
Steam boils off at the top of the boiler, and is collected and dried by being
passed through a series of narrow superheater pipes that pass back through the
larger smoke tubes, before being fed to the valves and pistons.
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1996 - the bare smokebox. |
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Photo by Phil Neale |
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1998, the engine with bare silver-painted boiler and black smokebox. |
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Photo by Phil Neale |
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1998 view of the smokebox. |
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Photo by Phil Neale |
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Inside the boiler barrel. The smoke tubes through the boiler will pass through this space. |
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The top of the barrel. These longitudinal stays help keep both boiler tubeplates in place under pressure. |
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The front boiler tubeplate from inside the firebox. |
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Each of these holes will be occupied by a smoke tube passing back to the opposite tubeplate at the front of the firebox. |
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View through the front tubeplate to the back one - a view that will be impossible after the smoke tubes are in place. |
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The rear tubeplate from inside the water space. |
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Summer view of the top of the firebox and boiler. |
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Peter removing the firebox stays. Note the rear tubeplate in the background. |
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This picture was taken through the firedoors. |
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Firebox outer wrapper during work on boiler cladding. |
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6023 on way to have her boiler lifted for restoration. |
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Boiler about to be lifted in Didcot's lifting shop. |
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Steady as she goes... |
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The boiler is lifted off the frames. |
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The firedoor and firebox outer wrapper. |
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The firebox outer wrapper. |
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For comparison, inside King George V's firebox, showing the grate, brick arch, and rear tubeplate, with tubes, beyond. |
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Smokebox and bolier barrel. |
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Trouble! The detection of flaws around the firedoor meant that two strips of metal needed removal and expensive replacement. |
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Note the view this shot gives of the hudreds of stays that hold the inner and outer firebox wrappers together. |
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Another view of the slot. |
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One of the pieces removed. |
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Rotated to show the rough inside surface. |
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The firedoor with two new pieces in the repair slots, awaiting welding. |
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Close up of one of the repairs. |
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6023 King Edward II Project
