4 ms·

There really isn't much to the engine of a steam engine. It's the firebox/burner and boiler where all the really hard and interesting stuff happens.

by TylerE 3y ago

sandworm101 3y ago
>> There really isn't much to the engine of a steam engine. Beware the train spotters. I hear a hundred steam-powered keyboards ready to rave about the intricacies of reverser gears.
- TylerE 3y ago
  Oh, I’m intimately aware. Just pointing my out that what most people call a steam “engine”… maybe only 10% of that is the actual engine. In something like a car especially. The actual engine is just a double acting cylinder and a few slide valves.
  - FrustratedMonky 3y ago
    I think the negative response to this type of post is because you can take any field and do a reductive statement "It's Just XYZ". There is a hundred years of steam engine design "It's Just some valves". It's just a way to either minimize someone's field, or way to show you only have a cursory understanding. Rarely does someone have a deep knowledge of a field and then also frame an overview of the field as "Just some bits". Nuclear Physics is Just smashing atoms. Biology is Just some Cells. Or Just looking through a microscope. Computer Science is Just the application of And/OR statements. Or Just Boolean logic. Internal Combustion Engines are just little explosion's in a cylinder. F1 Cars are just an engine + battery + some wings. Edit: Honestly. I'm guilty of doing this too. I've "Just Learned" how people take it so have learned to adapt phrasing things that don't insult people.
jcgrillo 3y ago
There is some interesting engineering in a compound double acting engine[1], especially one like the Doble which runs on superheated steam. There's a large temperature gradient between the "hot side" and the "cold side" where the hot side is something like 1250°F+. IIRC they had to be careful about getting the correct cast iron alloys, and the bores had to be slightly tapered. Then there's the valve train, which is totally different from an IC engine but sizing and flow considerations are still really important for efficiency. Also, your crossheads and bottom end bearings are potentially an area of concern--while rotational speeds are really low by modern engine standards, there's a problem of figuring out how to remove water from the lube oil. So I'd wager there's still a whole bunch of "interesting" things happening in the Doble engine, and we'd probably have a pretty difficult time building one from scratch today given that reciprocating steam engines haven't been "a thing" in industrial living memory. [1] For one example of an interesting problem: for a given temperature of inlet steam and desired power output, in a double expansion double-acting compound engine, tell me what size the hot cylinder will be, what size the cold cylinder will be, and what the clearances, rings, etc will be to make it all work efficiently across the operating envelope.
- TylerE 3y ago
  The Doble boiler is so much more interesting than that, though ;) Almost unique.
  - jcgrillo 3y ago
    It is very cool. I think we'd be mistaken thinking that any of this engineering is "trivial". This was the height of a technology that's largely forgotten, and unforgetting it would be hard work at every turn.
mannykannot 3y ago
If plethora of designs in search of perfection is an indicator of something of interest, then take a look at the many variations in valve gear design, particularly for locomotives, which needed to operate reasonably efficiently over a wide range of speeds, gradients and loads. Even more so, consider the many attempts at making non-turbine rotary steam engines, wonderfully documented here: http://douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng.htm http://douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng... My personal favorite is the Tower spherical engine: http://douglas-self.com/MUSEUM/POWER/tower/tower.htm http://douglas-self.com/MUSEUM/POWER/tower/tower.htm Unlike most of the designs here, this one was built and even put to a little practical use.
- uticus 3y ago
  > My personal favorite is the Tower spherical engine... when i first saw the static diagram, i thought wow that looks like it is much more complicated than this 2-d diagram lets on. then later down the page i saw the animation showing the 3-d complexity... mind blowing.
xenadu02 3y ago
Well the perfection of a steam-powered car was interesting even though technically far too late to matter. Early steam cars were more like steam trains: big boilers that need to be fired an hour before you want to go anywhere and need regular stops to take on water. In a Doble there technically isn't a boiler as most people think of it; the modern equivalent term might be "steam generator". The Doble system flashes water to steam almost instantly and on-demand, then uses a condenser to recycle the water. The flame is also not burning continuously, but only when steam is needed. With modern insulation materials the firebox is very efficient with little heat loss and lasts a long time. This gives the Doble steam car a responsiveness closer to a gas engine, without the need to pre-heat the boiler or continuously refill with water. The fuel system is more flexible too, it can operate on almost any liquid combustible with some adjustment. By the time the Doble was developed it was too late; gasoline and diesel won.
- jcgrillo 3y ago
  Part of the problem I think was that each Doble car was basically a one-off. They were expensive, high performance prototypes, not production consumer products. In principle they could have been made more user friendly--in terms of performance specs they were really close to a win (15mpg, powerful, quiet, low water consumption, fast starting) but they were still finicky, high maintenance machines. Higher production numbers could have driven solutions, but the Otto cycle had the advantage there. I wonder if you ran the 1890-1930 experiment 10 times how differently it all might shake out each time.
  - TylerE 3y ago
    The part almost no one talks about is how there are tons of cars being sold as early as 1880. They were just called horseless carriages, and were essentially a small carriage with… an electric motor and batteries. Yup, the original dominant form of car was an EV.

There really isn't much to the engine of a steam engine. It's the firebox/burner and boiler where all the really hard and interesting stuff happens.

by TylerE 3y ago

There really isn't much to the engine of a steam engine. It's the firebox/burner and boiler where all the really hard and interesting stuff happens.

sandworm101 3y ago

>> There really isn't much to the engine of a steam engine. Beware the train spotters. I hear a hundred steam-powered keyboards ready to rave about the intricacies of reverser gears.

TylerE 3y ago
Oh, I’m intimately aware. Just pointing my out that what most people call a steam “engine”… maybe only 10% of that is the actual engine. In something like a car especially. The actual engine is just a double acting cylinder and a few slide valves.
- FrustratedMonky 3y ago
  I think the negative response to this type of post is because you can take any field and do a reductive statement "It's Just XYZ". There is a hundred years of steam engine design "It's Just some valves". It's just a way to either minimize someone's field, or way to show you only have a cursory understanding. Rarely does someone have a deep knowledge of a field and then also frame an overview of the field as "Just some bits". Nuclear Physics is Just smashing atoms. Biology is Just some Cells. Or Just looking through a microscope. Computer Science is Just the application of And/OR statements. Or Just Boolean logic. Internal Combustion Engines are just little explosion's in a cylinder. F1 Cars are just an engine + battery + some wings. Edit: Honestly. I'm guilty of doing this too. I've "Just Learned" how people take it so have learned to adapt phrasing things that don't insult people.

jcgrillo 3y ago

There is some interesting engineering in a compound double acting engine[1], especially one like the Doble which runs on superheated steam. There's a large temperature gradient between the "hot side" and the "cold side" where the hot side is something like 1250°F+. IIRC they had to be careful about getting the correct cast iron alloys, and the bores had to be slightly tapered. Then there's the valve train, which is totally different from an IC engine but sizing and flow considerations are still really important for efficiency. Also, your crossheads and bottom end bearings are potentially an area of concern--while rotational speeds are really low by modern engine standards, there's a problem of figuring out how to remove water from the lube oil. So I'd wager there's still a whole bunch of "interesting" things happening in the Doble engine, and we'd probably have a pretty difficult time building one from scratch today given that reciprocating steam engines haven't been "a thing" in industrial living memory. [1] For one example of an interesting problem: for a given temperature of inlet steam and desired power output, in a double expansion double-acting compound engine, tell me what size the hot cylinder will be, what size the cold cylinder will be, and what the clearances, rings, etc will be to make it all work efficiently across the operating envelope.

TylerE 3y ago
The Doble boiler is so much more interesting than that, though ;) Almost unique.
- jcgrillo 3y ago
  It is very cool. I think we'd be mistaken thinking that any of this engineering is "trivial". This was the height of a technology that's largely forgotten, and unforgetting it would be hard work at every turn.

mannykannot 3y ago

If plethora of designs in search of perfection is an indicator of something of interest, then take a look at the many variations in valve gear design, particularly for locomotives, which needed to operate reasonably efficiently over a wide range of speeds, gradients and loads. Even more so, consider the many attempts at making non-turbine rotary steam engines, wonderfully documented here: http://douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng.htm http://douglas-self.com/MUSEUM/POWER/rotaryengines/rotaryeng... My personal favorite is the Tower spherical engine: http://douglas-self.com/MUSEUM/POWER/tower/tower.htm http://douglas-self.com/MUSEUM/POWER/tower/tower.htm Unlike most of the designs here, this one was built and even put to a little practical use.

uticus 3y ago
> My personal favorite is the Tower spherical engine... when i first saw the static diagram, i thought wow that looks like it is much more complicated than this 2-d diagram lets on. then later down the page i saw the animation showing the 3-d complexity... mind blowing.

xenadu02 3y ago

Well the perfection of a steam-powered car was interesting even though technically far too late to matter. Early steam cars were more like steam trains: big boilers that need to be fired an hour before you want to go anywhere and need regular stops to take on water. In a Doble there technically isn't a boiler as most people think of it; the modern equivalent term might be "steam generator". The Doble system flashes water to steam almost instantly and on-demand, then uses a condenser to recycle the water. The flame is also not burning continuously, but only when steam is needed. With modern insulation materials the firebox is very efficient with little heat loss and lasts a long time. This gives the Doble steam car a responsiveness closer to a gas engine, without the need to pre-heat the boiler or continuously refill with water. The fuel system is more flexible too, it can operate on almost any liquid combustible with some adjustment. By the time the Doble was developed it was too late; gasoline and diesel won.

jcgrillo 3y ago
Part of the problem I think was that each Doble car was basically a one-off. They were expensive, high performance prototypes, not production consumer products. In principle they could have been made more user friendly--in terms of performance specs they were really close to a win (15mpg, powerful, quiet, low water consumption, fast starting) but they were still finicky, high maintenance machines. Higher production numbers could have driven solutions, but the Otto cycle had the advantage there. I wonder if you ran the 1890-1930 experiment 10 times how differently it all might shake out each time.
- TylerE 3y ago
  The part almost no one talks about is how there are tons of cars being sold as early as 1880. They were just called horseless carriages, and were essentially a small carriage with… an electric motor and batteries. Yup, the original dominant form of car was an EV.