Roman Steam Engines

[BTD]

Leo mentioned in the book discussion about roman steam engines in AH, but in reality this isn't so far fetched as it might sound. The romans used steam powered machines to awe others. They made things from simple doodads that spun around to more complex door mechanisms. What if they had taken the next step, they had all the knowledges they needed they just had to put it together. What would have been the first roman uses of true steam power?

As steam mechanisms of the day were rather crude with limited capacity I think the first working use of steam engines would have been to make a simple pulley mechanism that could have been connected to a grinding wheel for grain or press for grapes/olives. I am sure that other inventors of the day would have quickly latched on to the idea as soon as the first workable engine was devised.

[Faeelin]

Actually, hero's engine might not have been a steam engine in the sense we think of it.

I can't see a Roman steam engine. People always underestimate just how difficult it is to build steam engines; look at the first ones people had historically, which were huge, and those were developed after people understood things like "air pressure".

[BTD]

Actually, hero's engine might not have been a steam engine in the sense we think of it.

no it wasn't what we think of as a traditional steam engine, it shot pressurized steam out of jets that propelled a sphere around an axle. However The romans did understand axles, wheels, levers and simple pneumatics. It wouldn't have taken too much to extend the axle into a drive shaft.

I can't see a Roman steam engine. People always underestimate just how difficult it is to build steam engines; look at the first ones people had historically, which were huge, and those were developed after people understood things like "air pressure".

I don't see them making a modern steam engine until they perfected some other techniques, such as a press for making uniform sheet metal, but small engines could have spurned on the drive to invent.

[Condottiero]

In fact it was more an economic problem than a tecnical one. What would be the usage of a steam machine if a slave is cheaper?

[BTD]

In fact it was more an economic problem than a tecnical one. What would be the usage of a steam machine if a slave is cheaper?

It is not neccesarily cheaper to use slaves, not to mention the romans did all kinds of things just because they did. Another thing these crude steam engines could have done is run pumps for fountains and to drain mines. Draining mines was rather costly when it cost slave lives. Another thing is it would not have had to make a big steam machine to start the rush of invention. One device that could have easily been converted was hand powered grain mill, which romans of the first century BCE had. It would not have been too much of a stretch to convert one of these with hero's engine as a base. Of course this would only have been done for its novelty at first but very easily could have sparked the rush of invention. Whiles hero's engine may not have powered a big mill, a big mill could easily have been powered by slaves or oxen once built. Larger mills in turn make the process of grinding grains, crushing grapes/olives or for that matter crushing ore. Think of what happens when you speed up the process iron production.

[Otis Tarda]

No, no, no! Let me use comparison: could US invent personal computer in late 30's? After all, US* had all stuff necessary - electronic lamps, some kind of theory of information, electricity. Moreover, IRRC, simple mechanical "calculators" were made in XVIIth century. However, we know that PC is something different than ENIAC.
The same story is with "roman steam engine". Hero's so-called "engine" has nothing to do with modern engine, it was just ball with two L-shaped pipes, which could spin when heated. There were others toys - statues that could "spit out" wedge from their mouth, for example. Still, it doesn't make an engine, as fireworks dosn't make a trip to the Moon.

I think, that we just underestimate technological leap made in Midlle Ages. Yes, there were not so many "new" inventions - but there was some progress in metalurgy, "practical" hydraulics (pumps were widely used), mechanics (for example turnery) - which made "real" steam engine aviailable.


* What is pronoun fo "US"? They? It? She?

[BTD]

The same story is with "roman steam engine". Hero's so-called "engine" has nothing to do with modern engine, it was just ball with two L-shaped pipes, which could spin when heated.

true it spun around, but it is not such a stretch to see someone extending one of the axles and putting a wheel on it and making a pulley system. This was not the only steam powered device it is also reported thet used a steam powered door opener for ceremony in some of the alexandrian temples. Whiles these were only used for shock and awe value, it isn't such a stretch to see someone like one of the famous inventors just taking it to the next level. Granted anything done would first be done for the sake of novelty, so is most of the research done in the country over the last 50 years.

[Croesus]

This subject is close to my heart; I've been working on a (grossly) fictionalized TL for about 8 years that, amongst other things, deals with this mouth-watering WI.

In the first instance, if you can, get hold of Arthur Toynbee's essay 'If Alexander the Great Had Lived On'. If you can't get hold of it, I can paraphrase the bits that relate to Hero's aeliophile.

Hero's party gimmick has been described in various hopeful terms by many writers over the years; the descriptions I tend to favour is that the device was a simple steam powered jet propulsion system, or a primitive reaction steam turbine. Certainly the device came in from left field and is great grist for the mill.

The aeliophile has all sorts of problems associated with it re. use as a source of motive power, but many of these are not insurmountable. From an alt-his pov things get tricky as you have to make more and more assumptions and you quickly get into the realm of fiction if you want to give the ancient world a steam engine (but that certainly hasn't stopped me).

Condotierro comes close to the main problem facing any counter-factual involving the aeliophile, by describing the situation as an economic issue not a technical one. However, the slave angle is a little over done (IMHO) and slightly misses the point. The key obstacle was intellectual, philosophical; the ancient world repeatedly prefers stasis over dynamism, the good and old over the brave and new, and consistently stops short of technological breakthrough because a heavily entrenched ideological conservatism that stretches back into the distant, idealised and ephemeral past.

As a case in point, BTD posits the first use of a steam engine as a power source for an agricultural press. I certainly agree that such a use would be among the first, but it took hundreds of years for the humble water wheel or wind mill to be hooked up to said press. This is indicative of this paradoxical lack of imagination and economic vision that so plagues the ancient world. The histories are full of the ancient world pulling up short of great things (one of the most frustrating was the length of time taken to increase the height and bore of the 'Catalan furnace' to obtain the 'wolf furnace' that historically gave us the the crucial stimulus towards effective steel making.

As I note above, the purist alt-historian will quickly stretch credulity by trying to anticipate industrial uses for the aeliophile. But that shouldn't stop you going down the fictional route and having more fun than a school bus full of kids trapped in Disneyland...

Croesus

[wkwillis]

The gearing necessary to take an efficient (high speed, so the spin matches the exhaust velocity) steam engine and use it for something usefull (separating cream for the first steam turbines) is hard to make using blacksmith's tools.
The machining for closely matched pistons was first used for cannon boring, IIRC, and only then adapted for pistons. The first reciprocating steam engines were atmospheric pressure designs. The steam displaced the air, then the steam was condensed on the walls of the piston, and the lower pressure sucked the piston down. Large, low power designs. At least they couldn't explode. Implode, maybe, if they jammed....

[DominusNovus]

The gearing necessary to take an efficient (high speed, so the spin matches the exhaust velocity) steam engine and use it for something usefull (separating cream for the first steam turbines) is hard to make using blacksmith's tools.
But the Greeks did manage to produce very good gears. The Antikythera mechanism, Archimedes' odometer, and many of Heron's works all attest to this. The gearing would not have been much of a problem.

[wkwillis]

1. Efficient steam engines require that the exhaust velocity of the steam output approach the speed of the nozzle. But the device doesn't need to be efficient if the fuel source is cheap enough. Maybe waste fuel gas from distilling trees? They had distillation then. A market for charcoal and turpentine existed...Possible.
2. Direct contact gears don't have to be used. Some kind of pneumatic power transfer maybe? Scupting the turbine blades for a pneumatic reduction gear could be done if you accepted a lossy transmission.
3. With enough work they could balance a gear decently. They don't have to use iron. They could use copper or bronze. Those are easier to work. They did have lathes in the form of potter's wheels.
4. Bearings could be made by...at this point I give up. It might be possible by some technique I haven't considered. They did build one, after all. And again, it doesn't have to be efficient if the fuel is waste from something else.

I would go with big, slow, reciprocating pistons. Tensile instead of compressive, atmospheric rather than pressurised. Like the first steam engines in Bohemia that were used to pump water out of mines.

[wkwillis]

Ah hah! I got it. Use a boiler to make pressurised steam, but it's not sealed! Avoid the entire sealing problem by making the steam push down on the water in a siphon until the water spills over onto a water wheel. If you are short of water and have enough fuel, you can run the whole works off the gearing for a conventional water wheel. Those they had and knew very well.
Now, what do you use it for that needs to operate in the dry season, or where there is plenty of fuel and no water power? Or wind power is too undependable?
Steam hammers for forging iron? Grinding ores? Pushing air around in a mine or a blast furnace? They did use chimney drafts to suck air around. Drilling a mine shaft by dropping a heavy weight down a hole and hauling it (and the rock) back up? Pumping water for irrigation using straw for a fuel?
Come to think of it, you could use it to run a weighted pickaxe rig with a rope to drill into a rock layer, especially a horizontal one. They didn't have gunpowder so mining was difficult. You had to bash the rock with a pickaxe till you could pry. With a rope system for power you could run ropes into shallow mines in the hills and just have the guy guide the force, instead of providing it.
You would have several square miles of hillside forest and a dozen families cutting the wood for a one man mine, with charcoal for a salable byproduct. Also oily fuels that separate from the steam condensing from your big copper pyrolysis facility. The fuel gases would run your mine. The watery products like acetic acid, acetone, and methanol might be distillable. Ammonia? That would be good for fertiliser, as the shale oil production people found when they just let it run into a meadow or something.
How resistant is copper to pyroligneous acid? Would you have to use cheaper iron instead? It is more difficult to make into pipes than copper.