Quote:
Originally Posted by Pride of Somerset
But surely it is - we are talking about two completely different things here aren't we??
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Priming is the carry over of water droplets from the boiler to the cylinder with the steam. The main causes are:-
Too much water in the boiler.
Dirty water in the boiler which may foam or have sludge floating on the surface.
A worn piston and or cylinder bore which makes the engine use steam so fast that it pulls a string of water with it.
Rough handling of the engine.
Priming is accompanied by hammering in the cylinder as water cannot be compressed and often results in bent -and -broken bits of engine in severe cases.
'White' steam at the chimney top is a result of low fire temperatures-and therefore low gas temperatures which allow the exhaust steam to condense when the steam reaches the air. Some engines have very airtight ashpans which stifle the fire, and therefore cause white steam, conversely if you have watched the replica steam carriage called Enterprise you never see steam from that as the exhaust is reheated in a heat exchanger in the boiler.
Charlie D