But this (500=B0C) isn't the temperature of the heat source, it is the temperature of the steam at the hottest part of the cycle. The heat source (combustion products) is more likely to be at around the 2000=B0C mark. This is one of the major sources of thermodynamic loss in a steam cycle, largely corrected for in the GT combined cycle.
Robin
The idea of the Velox as an inspiration for gas turbines is an interesting one, but the gas turbine (in theory at least) goes back to the 18th century. They didn't need the Velox boiler to inspire them.
Neuchatel wasn't the first gas turbine. There were a number in service in the US before this, running with blast furnace gas.
to ignore Harry.
One of the few UK companies to use them was the LNER - including Blue Peter, as mentioned alredy, the loco that suffered the worst priming accident of recent years.
I'd never considered this as a deliberate measure against damage from priming, but it's an interesting idea. After all, in loco practice, this large clearance still hung around until Churchward decided to deliberately remove it, around 1900. For stationary engines, Stumpf recognised it as a bad idea, after realising the importance of re- compression at the end of stroke, for efficiency purposes.
I'm not sure it /was/ a deliberate feature of the Hedley machines - more the consequence of re-using the casting patterns[1] from a horizontal
-cylinder Trevithick (type?) engine in a vertical position - that also left them with an immensely long stroke which forced the use of gearing (the Trevithick locomotive of 1805 was, of course, geared..). Now, whether Trevithick left that clearance in because he expected water to be carried over into the cylinder is another question .. My suspicion is he'd one it as an insurance, expecting boilers to be over-filled and priming to occur, even with stationary engines (in all cases a Trevithick engine would be the first high-pressure, compact engine its operators would have seen - the scope for mis-handling would be immense...). OTOH, with the cylinders outside and no real lagging, it's hard to see how the Hedley machines could have worked (especially on short-railed plateways, with the resulting violent fluctuations of water level in the small boiler) without that amount of clearance.
[1] Rather crudely converted to use slide valves in place of the 4-way c*ck - the amendation is apparently quite clear in the cylinders of the two surviving machines..In message , harry writes
I remember being told about a fusible plug coming away on a preserved Black 5 on the S&C some years ago. IIRC correctly the plug had been cross-threaded and no one noticed. The loco wasn't fitted with a rocking grate and I was told the crew had to shovel the fire out through the cab rather than just being able to drop it.
Sam
Not at all. The counter-example os to look at American boiler explosions, which largely happened on steamboats with low-pressure box boilers.
In message , Sam Wilson writes
The usual way to drop a fire is by removing about six bars of the grate and scraping the entire fire into it. Fire-droppers had a special hooked fire iron to whip out the bars with and could drop a complete fire in a matter of minutes. You couldn't shovel out a fire as a fire iron is of no use towards the firehole doors and a standard shovel would just catch fire if you attempted to remove burning coals with it.
The standard way for a very long time on stationary boilers was a wooden float on the water level, linked through a wire or cord to the outside. As pressures were low, leakage and mis-reading due to pressure effects weren't a problem. This was used on ships too, but was unsuccessful on locomotives (although it was tried), owing to the float being shaken around - it worked when stationary though.
That would mean a small hole in the top of the boiler, then? That should be reasonably easy to check for on the surviving locomotives if it was used (the photographs of the inside of Wylam Dilly's boiler in ER2 that I'm looking at don't seem to show any such thing, though, nor is there any sign of it in the diagram of boiler plates from both the surviving Wylam engines in the same article..).
I'm getting more and more sure there's some subtlety in the way these early machines were operated that I'm missing - some lost art of working those boilers...
'Twas ever so. New tchnology comes along, and the old ways get lost.
How many people can properly set the mixture on a gas lamp nowadays just by looking and listening?
I could a few years ago, back when the electricity supply out here could be a bit intermittent and (bottled) gas lamps were one of my standbys. Not sure I could do it now, at least not without a few goes.
OK. Such things should be easy to check for on surviving early locomotives (sadly, I don't have one to hand...).
I'm not seeing such a fitting (or signs of one) on the photographs of the Wylam engines, Agenoria or Locomotion that I can call on from here, but I've not actually got any close-ups of the boiler top in any of those cases..
Anyone used to a bunsen burner perhaps.
Yes don't suppose in those days they read the 'effing manual either then
Mind you they prolly had a decent excuse in they couldn't read it anyway;!...
I was told that in days of olde when the Cambridge water co built their first reservoir up on Lime Kiln Hill they used a long pole with a flag thereon which rose and fell depending on the water level.
An engine man some distance away used that seen via a telescope to judge how much water to pump uphill..
And no I don't know what they did on foggy days, suppose they had a bloke on a horse ride up there to have a butchers;!...
Wouldn't be one (how could there be, with the first engines..). "Write it if you get the chance". Stephenson does seem to be the first to think about transferring expertise in how to work a locomotive (mind, wasn't he copying what Boulton and Watt had done with stationary engines - supply someone trained to worK the engine as part of the package?[1]).
It's noticable how many of the early engine drivers became great men in the developing railways - Daniel Gooch and Edward Fletcher were two of Stephenson's drivers... Really, in terms of career progression (if you didn't meet an early end) it must have been a bit like being a computer engineer in the early
1960s (or the Web 2.x lot a few years ago..).HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.