3D teaching model · 12 seconds · Captioned
The Newcomen engine’s power stroke
See how a drop in pressure beneath a piston allows atmospheric pressure to push it downward, rocking a beam and lifting a mine pump rod.
Explore this mechanism in interactive 3D →
Follow the mechanism
- 0:00
Steam has filled the space beneath the raised piston. The top of the cylinder is open to the atmosphere.
- 0:03
Cold-water injection condenses the steam and lowers the pressure below the piston. The injection apparatus is omitted from this diagram.
- 0:06
Atmospheric pressure pushes the piston down. The rocking beam lifts the pump rod on the opposite side.
- 0:09
This is the end of the power stroke. A real engine must admit steam again and reset before repeating; the return stroke is not shown.
What the model simplifies
A mechanism diagram inspired by the Newcomen atmospheric engine, not a reconstruction of a surviving machine. The cylinder front is removed. Colour marks the space beneath the piston, not visible steam. Chains, valves, injection apparatus and the return stroke are omitted. Linkages and proportions are simplified; this is one power stroke, not a complete working cycle.
Place it in history
Newcomen’s engine: draining mines with atmospheric pressure →