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Watt's Steam Engine


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This is a working model of James Watt's steam engine. Watt did not invent the steam engine as such, before him there were Savery and Newcomen. But his improvements have increased the usability and efficiency of the 'fire engine' so much that it made a break-through to all branches of industry, empowering the industrial revolution.

The model represents a beam engine, with an upright cylinder and a large flywheel. The to-and-fro motion of the piston inside the cylinder is taken up by the large beam, and then converted to a rotary motion by Watt's very own planetary motion gears. To make the piston rod on the end of the rotating beam travel in a completely straight path, a system of levers called Watt's parallelogram is employed. A sliding valve driven from the main crankshaft steers the intake and outlet of steam.

The machine also includes a speed governor, an air pump for the steam condenser, and a feedwater pump.

The model actually runs on a gentle vacuum, as provided by carefully approaching the steam outlet with the hose of a vacuum cleaner.

There are 669 bricks in this model. The build is quite challenging; the hardest part is adjusting all the parts to move really freely, and then centering the motion of the slide valve. When finished, the rigid frame stabilizes the engine so it can easily be picked up and handled without coming out of adjustment.

This is for those Lego fans who don't like to limit themselves to stationary builds. You can literally get your hands on the complex motion of the various elements, which taken together are more than the sum of their parts: A machine to turn fire into work.