Steam engines and sub-machines
as of 0.8.0
An engine draws steam from a pipe network and drives exactly one sub-machine. One engine, one sub-machine: a setup that wants both pumped water and turning axles needs two engines, and two boilers to feed them.
The Watt Beam Engine
A low-pressure beam engine, raised through right-click construction the same way a boiler is. The whole build is 4 metal plates, 24 rods, 12 nails and strips and 36 fire bricks.
| Quantity | Value |
|---|---|
| runs at | 2.0 atm inlet steam and above |
| wears and breaks above | 4.0 atm |
| seconds over its band before it breaks | 60 |
| steam drawn while running | 30 L/s |
| power delivered | 0.3 |
| condensate out of its drain | 1 L/s |
The engine's inlet is always at the back, because the machine always faces one way. Its drain dribbles hot condensate that can be piped back toward the boiler or left to spill.
Pushed past its band for too long, the cylinder bursts and the piston is damaged. Right-click it with a wrench in hand to see the repair bill, then again with those materials in the hotbar to mend it.
Power
Power is a bare number, not watts or newton-metres. What it means is what it can carry, and the two sub-machines convert it differently.
The Engine Crank turns vanilla axles. Its budget is
budget = power * 0.875 * rated speed
with a rated speed of 1.0, so a Watt Beam Engine at full power holds the network at rated speed against a load of up to 0.26. Heavier loads drag the speed down as budget divided by load; past double the rated load, about 0.53, the engine overstresses and stops. For scale, a vanilla helve hammer's resistance is about 0.175 and a waterwheel produces far more than any engine here. A steam engine is deliberately worse than a waterwheel; what it buys is placement and power on demand.
The Engine Fluid Pump moves water from its intake line to its output line at 50 L/s per unit of power, which is 15 L/s on a Watt Beam Engine, and pressurises the output to 0.75 of the engine's inlet steam pressure. That is enough to lift water into a boiler, which is what closes the water loop.
Fitting a sub-machine
Place the engine first and raise it through its stages, then set the sub-machine in the cell directly beneath the beam's pumping rod. It snaps itself to the correct facing.
Step by step
- Raise a Watt Beam Engine near the boiler, with its back toward the steam run.
- Pipe the boiler's steam outlet to the engine's inlet through a Piping (Pressure Valve) gated between 2 and 3 atm, since a Cornish Boiler chokes at 5 atm and the engine breaks at 4.
- Give the pressure valve's output somewhere to go, or accept that it vents.
- Set the sub-machine in the drive cell under the beam.
- For an Engine Fluid Pump, pipe a Fluid Intake into its intake side and its output into the boiler. The water loop then feeds itself for as long as the coal lasts.
- For an Engine Crank, run axles off it to whatever is being driven.
What goes wrong
The engine does not start. Inlet pressure is below 2 atm. Build pressure before starting rather than during.
The engine broke with a valve fitted. The gate was above 4 atm, or the valve was flipped and was never holding anything back. The copper-trimmed ring is the input side.
One engine will not run a pump and a generator. It cannot. Fit one sub-machine; build a second engine for the second job.
The network stalls under load. The load is past double the engine's rated figure. Shed machines or add drive.
The engine's input face cannot be found. It is always the back face. The machine has one facing and the inlet does not move.