How It Works

What was the beam engine?

The beam engine was used to draw out water from mines, as well as to pump water into canals. The engine consisted of a large wooden frame into which a pivoted overhead beam was used to apply force generated by a vertical piston and transfer that movement to a pump rod.

The piston’s movement was driven by a coal-heated boiler, which generated steam and fed it into the piston’s cylinder.

When the piston was at its apex – moving the beam and dropping the pump rod – the cylinder was injected with cold water, creating condensation and eventually a vacuum, thereby drawing the piston down and raising the pump rod again in a cycle.

Early beam engines (eg Newcomen’s) were quite inefficient due to their lack of a separate condenser, but this was improved upon by later models like the Watt steam engine.