Interactive mechanism · source-grounded teaching model
The Newcomen cycle
Follow a full motion cycle: the piston descends during the power stroke and rises again as the heavier pump side descends. Pause and turn the engine to compare the two movements.
1 / Ready for condensation. Steam fills the cylinder; cold water admission will condense it.
Piston. After steam condenses below it, atmospheric pressure above the piston drives it downward.
Power, reset and repeat
The problem below ground
Flooding limited the depth of mines. The Newcomen engine used a piston, rocking beam and pump rod to remove water. Its first successful installation near Dudley in 1712 drew on both scientific investigations and the skills of craftspeople working in wood, metal and masonry.
How the power stroke worked
Steam entered an open-topped cylinder beneath the piston. Injected cold water condensed the steam, lowering pressure inside the cylinder. Atmospheric pressure above the piston then pushed it downward. Through the rocking beam, that downward stroke raised the pump rod at the opposite end.
Every part, in words
Piston. After steam condenses below it, atmospheric pressure above the piston drives it downward.
Beam. The rocking beam links the two ends: piston down means pump rod up.
Return weight. When steam is admitted again, the heavier pump side descends and pulls the piston back upward. Steam pressure does not lift the beam as in a later high-pressure engine.
Cylinder space. This coloured space changes with piston position. Condensation, pressure and water flow are described, not calculated.
