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Steam Engines

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Re: Steam Engines
Post by AirTech   » Tue Mar 11, 2014 8:41 am

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WES wrote:One of the last new lines of inquiry raised in LAMA was when the idea of steam engines was presented to Clyntahn.

Charisan steam engines use 300 pounds pressure, although early steam engines used a little as 25 pounds. I have know about the principles of steam engines for many years, however, understanding the principles of steam engines does not make them easy.

Examples:

1. Valve Gear
2. Lap and Lead (adjustment of valves)
3. Reverse Gear (Johnson Bar)
4. Sight Glass (for determining boiler water level)
5. Stay bolts (fixed and flexible)
6. Low water alarm
7. Throttle
8. Injectors (to inject water into the boiler against the steam pressure - 2 required)
9. Blower
10. Drain Cocks (on face of backhead to determine water level)
11. Cylinder drain cocks
12. Steam Pressure Gauge
13. Steam Safety Valves
14. Rocker grates (in firebox)

Steam Engines also use AIR to control many of the above.

Steam Engines may throw a wrench in Clyntahn's plans long term but the only thing the knowledge will provide for 2-3 years is an appreciation by Thrisk of the advantages and limitations of steam engines in consultation with his technical guru.

The only caveat to this if the Author expands the principles explained to Clinton, et al, in DETAIL (and books are written on this subject and "hands on" experience was understood to be needed by the readers).


A crude steam engine can do away with a lot of this, an atmospheric engine like the early Newcomen or Watt engines eliminates most of these as the boiler can be gravity fed, valve gear is optional (the early ones were manually valved) and the clearances were on the order of a 1/4 inch. Complicating them to the point of a 20th century marine engine just makes it hard for the Church to replicate (thermal efficiency is definitely a benefit (1% vs 40%) and for long range cruising, essential). (BTW the early Newcomen and Watt engines work at ambient pressure and use air pressure to drive the piston against a vacuum generated by condensing the steam in the cylinder).
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Re: Steam Engines
Post by isaac_newton   » Tue Mar 11, 2014 12:18 pm

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AirTech wrote:
WES wrote:One of the last new lines of inquiry raised in LAMA was when the idea of steam engines was presented to Clyntahn.

SNIP

The only caveat to this if the Author expands the principles explained to Clinton, et al, in DETAIL (and books are written on this subject and "hands on" experience was understood to be needed by the readers).


A crude steam engine can do away with a lot of this, an atmospheric engine like the early Newcomen or Watt engines eliminates most of these as the boiler can be gravity fed, valve gear is optional (the early ones were manually valved) and the clearances were on the order of a 1/4 inch. Complicating them to the point of a 20th century marine engine just makes it hard for the Church to replicate (thermal efficiency is definitely a benefit (1% vs 40%) and for long range cruising, essential). (BTW the early Newcomen and Watt engines work at ambient pressure and use air pressure to drive the piston against a vacuum generated by condensing the steam in the cylinder).


IIRC those early engines were used for mine pumping and such, and I believe, were pretty big beasts. Given that, could they be realistically be used in Thirsk's screw galleys?

[Edit]
The wikipedia entryhttp://en.wikipedia.org/wiki/Steam_engine has an interesting article on the history - seemed to have taken about 50 years to go from Newcommen's stationary engines to Watts versions, and yet more decades to get to get to true stream driven systems [rather than the original atmospheric devices]
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Re: Steam Engines
Post by Gunny   » Tue Mar 11, 2014 5:29 pm

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pushmar wrote:By the way, they even made a steam-powered airplane in 1933, with a reversing gear for VERY short landings.

http://blog.modernmechanix.com/worlds-f ... -airplane/

A steam powered airplane was made possible by the invention of the flash boiler. This is basically a coiled tube in the path of a blow torch. You get the coil red hot. Then you pump in water, it flashes to steam almost instantly. With its small volume of water/steam and no big water storage in the boiler it is much, much lighter than a traditional boiler.

Several steam automobiles, White, Doble, Gardner-Serpollet to name a few, made cars with flash boiler. They had the advantage of being much faster to get up steam than a traditional type like the Stanley.

You need pretty good steel to make the tube, and I don't think you could fire one with coal.
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Re: Steam Engines
Post by alj_sf   » Tue Mar 11, 2014 6:24 pm

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pushmar wrote:By the way, they even made a steam-powered airplane in 1933, with a reversing gear for VERY short landings.

http://blog.modernmechanix.com/worlds-f ... -airplane/


Not the first steam airplane by quite far :

http://en.wikipedia.org/wiki/Ader_%C3%89ole

While Eole claim to be the first airplane is quite a bit impaired by the lack of directional controls, there was other attempts of steam airplanes in the 1910 era.

The Eole plant was good both in power and lightness but its propeller and wings were very inefficient. The plant was 90kg for 20 hp to compare with the 80kg for 12hp of the Whright brothers one.

Note that Eole other name, Avion, is now the French name for airplanes.
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Re: Steam Engines
Post by jmseeley   » Tue Mar 11, 2014 8:09 pm

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lyonheart wrote:Hello WES,

Welcome to the Forums, enjoy your favorite simulated beverage on the forum.

Thanks for the instrument list!

Kudos for the excellent points!

I think many of us are agreed that knowing the principles doesn't mean you can automatically build a steam engine, let alone the gearing to make it useful.

Getting Watt's pistons and cylinders properly drilled and sealed was almost impossible until John Wilkinson lent a hand.

While our CoGA geniuses may quickly use their cannon boring machinery, "they've only just begun" as your list of controls demonstrate.

While some are intuitive, some result only from painful experience, which also takes a lot of time, which I don't think the Go4 has.

Fultyn and Zhwaigair may telescope the development period considerably, going through the Savery and Newcomen engine stages fairly quickly (their workmen will need the experience), but it will still take some considerable time to learn all the 'unknown unknowns' at this point.

I also believe the steam engine will be a resource sink for the Go4, though they may think they've solved the various problems soon after the war when they get a look at one, though the current Charisian models are so superior, they might be even become more confused.

Spreading steam engine technology across Safehold is one of Merlin's goals, so he'll support their survival and ultimate success after this current war.

But the process will be fun to watch. ;)

L


Charis was able to develop useful steam engines because they knew what the finished product looked like, as well as the shortest path to it. Clyntahn has a functional description, but that's not enough to do it quickly. I'm worried that he'll simply throw the data at his tech people and tell them to build it. Zhwaigair is a genius at getting to a 90% solution, but this may be beyond him (at least on a short deadline). And we know how Clyntahn responds to people who tell him 'no'.

If he CAN deliver, then the question is what do they use it for? Charis uses it to increase productivity, but they redesigned their industry to accommodate it. The Church won't really have that luxury. If they try, as you said, it will be a drag on their productivity, especially since it will draw in their most valuable people.

The most likely use would be in the crank galleys, IF Zhwaigair can make it small enough. Probably not as its main power plant, but available for a 'combat sprint'.

jms
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Re: Steam Engines
Post by AirTech   » Tue Mar 11, 2014 11:56 pm

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Gunny wrote:
pushmar wrote:By the way, they even made a steam-powered airplane in 1933, with a reversing gear for VERY short landings.

http://blog.modernmechanix.com/worlds-f ... -airplane/

A steam powered airplane was made possible by the invention of the flash boiler. This is basically a coiled tube in the path of a blow torch. You get the coil red hot. Then you pump in water, it flashes to steam almost instantly. With its small volume of water/steam and no big water storage in the boiler it is much, much lighter than a traditional boiler.

Several steam automobiles, White, Doble, Gardner-Serpollet to name a few, made cars with flash boiler. They had the advantage of being much faster to get up steam than a traditional type like the Stanley.

You need pretty good steel to make the tube, and I don't think you could fire one with coal.


Flash boilers are also used in coal thermal power plants because they have a better load swing characteristics (conventional steam drum types take up to 2 hours to go from idle to full power, flash (once through) boiler can reduce this to 30 seconds). The bite in the backside is that the boiler controls make a nuclear power plant look simple (and safe).
(Smaller conventional package boilers take around 5 minutes, worth noting when you look at steam engine throttle response in unit mode (i.e. unit mode - changing boiler input firing to change engine speed, station mode - restrict the engine steam inlet and vent excess steam)).
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Re: Steam Engines
Post by AirTech   » Wed Mar 12, 2014 12:21 am

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lyonheart wrote:Hello WES,

Welcome to the Forums, enjoy your favorite simulated beverage on the forum.

Thanks for the instrument list!

Kudos for the excellent points!

I think many of us are agreed that knowing the principles doesn't mean you can automatically build a steam engine, let alone the gearing to make it useful.

Getting Watt's pistons and cylinders properly drilled and sealed was almost impossible until John Wilkinson lent a hand.

While our CoGA geniuses may quickly use their cannon boring machinery, "they've only just begun" as your list of controls demonstrate.

While some are intuitive, some result only from painful experience, which also takes a lot of time, which I don't think the Go4 has.

Fultyn and Zhwaigair may telescope the development period considerably, going through the Savery and Newcomen engine stages fairly quickly (their workmen will need the experience), but it will still take some considerable time to learn all the 'unknown unknowns' at this point.

I also believe the steam engine will be a resource sink for the Go4, though they may think they've solved the various problems soon after the war when they get a look at one, though the current Charisian models are so superior, they might be even become more confused.

Spreading steam engine technology across Safehold is one of Merlin's goals, so he'll support their survival and ultimate success after this current war.

But the process will be fun to watch. ;)

L



Watts pistons and cylinders were not machined, they were cast and hand scraped. The sealing was achieved with the leather gaskets and lapping compound (and a lot of time).
The early marine lever engines on the side wheel steamers used engines indistinguishable from pumping engines - just the output device changed. The low efficiency and enormous size would prevent a powered assault on Charis (crossing the Atlantic required a ship the size of the Great Eastern to just to hold the coal, so steel ships have to come first unless you can magic up a high pressure boiler or two and a compound steam engine - on Earth this happened together).
High pressure steam requires precision machining (especially for the piston rings), as does breach loading rifled cannon. If you can build a high pressure steam engine, a diesel is a doddle to build but you need the fuel first - which requires a refinery, which requires steam to drive the heating and pumps (direct fired heating is possible but unhealthy if you are careless).
Seriously high pressure steam requires high strength steel.
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Re: Steam Engines
Post by chrisd   » Wed Mar 12, 2014 6:55 am

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WES wrote:Examples:

1. Valve Gear
2. Lap and Lead (adjustment of valves)
3. Reverse Gear (Johnson Bar)
4. Sight Glass (for determining boiler water level)
5. Stay bolts (fixed and flexible)
6. Low water alarm
7. Throttle
8. Injectors (to inject water into the boiler against the steam pressure - 2 required)
9. Blower
10. Drain Cocks (on face of backhead to determine water level)
11. Cylinder drain cocks
12. Steam Pressure Gauge
13. Steam Safety Valves
14. Rocker grates (in firebox)



I may be mistaken but the equipment described here by "WES" seems to me to apply more to a STEAM LOCOMOTIVE than to a Marine Steam Plant. (?)

Steam locomotives ( British practice) are where I have most of my experience, but, here goes:-

Injectors are not generally used in marine practice, steam driven "Feed pumps" are preferred, either direct acting (Weir type) simplex or duplex or indirect with an intervening flywheel.
(Injectors, being a French invention are inherently temperamental and unstable! and thus unsuitable for use on long sea voyages.)

A "Blower" is a locomotive fitting. Marine practice either relies on natural draught through tall funnels or either forced draught or induced draught with mechanically driven fans. Again, added complexity increases maintenance and/or increases unreliability
(I subscribe to the "Perverse Square Law of Reliability" - i.e. Double the complexity, Quadruple the chances of a breakdown.)

(Item 10) Drain Cocks are obsolete for determining Boiler Water levels, as well as being difficult to read accurately. Some boilers may still be fitted with them as an absolute emergency back-up for the glass tube "Sight Glasses".

Rocking Grates are a rarity in Marine Practice. They tend to be a latter day locomotive item where rapid turn-round between runs is required, with a labour-saving bonus as well.

As Marine engines are generally "Vertical" the valves need to be set asymmetrically to allow "cush" steam at the bottom of the downstroke, especially on the low-pressure cylinders. valve gear used at sea is USUALLY Stevenson's although variants on "Marshall's and Joy's gear are used in some instances.
On "really large" engines, some provision must be made, usually with a steam cylinder , to support the physical weight of the very large, low-pressure slide valves.
In some cases the L.P.Cylinder is split into two smaller cylinders of the same swept volume as the one large cylinder., but I don't think that Charis/Howseman has yet reached this size of engine

Are they using condensers exhausting to vacuum? Considerable gains in efficiency are available here at the expense of considerable complication of machinery with the vacuum pumps etc. needing to be driven

I am assuming that the boilers will be the "Scotch", shell-and-fire-tube, type. more complicated than the Lancashire but less complex that the Belleville, Babcock and Wilcox, Niclausse, Normand and Yarrow water tube types, extensively used in NAVAL marine installations.
300psi, as quoted, is very near the higher practical pressures that can be used with a Shell-and-tube boiler and in-service maintenance at these pressures becomes onerous.
I assume that the boilers are merely providing "dry, saturated" steam as superheaters were not common in marine practice, their benefits being outweighed by the increased maintenance and bulk of the installation.

I am refreshing my information on Marine Steam with reference to "The Marine Steam Engine" 3rd Edition 1898 by R. Sennett and H.J. Oram - both engineers to the Admiralty so the book is biased towards Naval Practice.
Last edited by chrisd on Wed Mar 12, 2014 9:38 am, edited 4 times in total.
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Re: Steam Engines
Post by pokermind   » Wed Mar 12, 2014 8:06 am

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So far no seamless tubing extruders in canon to make flash boilers, not they are not coming. Besides boilers thick walled steel tubing to make rifle barrels are needed ;)

Early steam engines used low pressure and although huge (they filled buildings) produced limited horsepower in the 5-15 HP range. Early boiler plates were caulked with lead and canvas, 70 PSI was high pressure, and higher melted the lead leading to very un-good results.

Poker
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"Better to be hung for a hexapuma than a housecat," Com. Pang Yau-pau, ART.
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Re: Steam Engines
Post by chrisd   » Wed Mar 12, 2014 9:12 am

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pokermind wrote:Early steam engines used low pressure and although huge (they filled buildings) produced limited horsepower in the 5-15 HP range. Early boiler plates were caulked with lead and canvas, 70 PSI was high pressure, and higher melted the lead leading to very un-good results.

Poker


If you get the chance to see the former pumping engine at Elsecar near Barnsley, a Newcomen engine still in place at its original installation site, you will find that it operates at 1.5 psi (IIRC) and all the steam pipework is genuine plumbing (made of lead)
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