The Beam Engine Animation

Background

The up and down motion of the piston in the cylinder is transmitted by the beam to the piston in the water pump. The steam cylinder piston goes down under the pressure of steam and differences in atmospheric pressure created by the partial vacuum beneath the piston. The beam, powered by the cylinder piston, pulls up the water pump piston. At the end of the downward stroke, the steam pressure is released and the steam cylinder piston returns to its original position because it is dragged back up the cylinder by the weight of the pump rods at the other end of the beam.

The Kew Bridge Steam Museum in London has the largest working Cornish Steam Engine in the World. It was actually built for the site to pump water to West London and started work on the 30th May 1846. It was only taken out of service in 1944 - a working life of just less than a century. The massive engine was constructed for the Grand Junction Water Works company and is able to pump 472 gallons in just a single stroke. The beam, which is made from cast iron, weighs a staggering 35 tons. The engine was transported from Cornwall to London by ship, before being loaded onto a barge for the journey up the Thames River.

There are smaller beam engines such as one from Boulton and Watt that can be seen at the Kew Museum. The engine was built around the time of Watt's death in 1819 and it was moved to the site in 1839-40. James Watt's inventions meant that the steam engine became much more economical to use and thus he helped to set in motion the Industrial Revolution.