(526) How the steam-engine works

A thumbnail lecture on the steam-engine

  For my evening entertainment I give a thumbnail lecture on the steam-engine.

By A. FREDERICK COLLINS
Copyright, 1918, by Frederick A. Stokes company

  This book says in its last chapter "some evening entertainments", everyone is interested in steam because it is one of the great prime movers, such as water or wind, but there are very few people indeed who have any idea of how a steam engine works. If I follow this book's instruction I can talk on the principles of a steam engine so that, whatever the age of my listers, all of you will know, when I'm through, exactly how and why a steam engine runs and develops power.

  There are two problems here, though. One is this book, titled "Handicraft For Boys" was published in 1918, more than 100 years ago. The other is I don't bring the hand-made model of the engine to demonstrate its action for you. But anyway, I'll start. First of all, the steam-engine is an old-fashioned machine, but very attractive one. You know this book? Many children love steam-locomotive characters in "Thomas and his friends".

First published in Great Britain 2010
by Egnont UK Limited

This is a model engine constructed from diagrams shown in this book, "Handicraft For Boys".

This model doesn't run by steam, but one made almost entirely of wood and the purpose of it is not actually to produce power but to show exactly how it works.

If you will turn the fly wheel around with your hand, you will see exactly how the slide valve opens first one port in the cylinder and then the other and that when the port is open which gives a clear path for the steam to flow from the steam chest to the cylinder (colored purple), the other port is connected to the exhaust pipe , when the used steam passes into the open air (colored pale blue).

https://www.jyotetsu.co.jp/botchan/

  Here is another model engine in Matsuyama city. You can see a model engine in today's Botchan train's body. Its structure is very similar to the model engine made of wood. In Botchan train's replica of engine, in stead of your hand, the diesel engine turns its rear wheel around, you see exactly  how the crank rod (⑥) and the valve gear move. The crank rod (⑥) is colored pale brown. It is jointed to the piston (⑤). The valve gear is colored white in the diagram. On the piston's cylinder there is a sliding valve box and the steam-chest, from which two pipes are connected to the steam dome and the chimney respectively.

① firebox, ② tubes, ③ steam dome, ④ steam intake pipe, ⑤ piston & cylinder, ⑥ crank rod, ⑦ connecting rod

 http://railway2.web.fc2.com/bocchan/bocchan.html
Mirror image of the original pictures

  In the original Botchan steam locomotive, the power of steam moves the piston head back and forth by the work of the slide valve. The piston rod drives the crank rod (⑥) on the rear wheel. Steam produces reciprocating action of the piston. This action turns the rear wheel around by the crank rod (⑥).

  Today's Botchan train is equipped with diesel-powered engine, but it is serving as tourist attraction and a perfect model train demonstrating how the steam-engine works.

Now, you can talk on the principles of a steam engine by Botchan train's body.

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