As promised, even if people do find it hard to pick out the points they need from a thread, Iím going to forge ahead with simple steam postings.
After explaining the principles of boiling water and getting the most from it I think an explanation of different boiler types and their relative advantages and disadvantages-
Following on from explaining that heating surfaces and boiler shapes are the most effective means of controlling the boiling water.
I will explain using examples both full size and model- the principles are EXACTLY the same.
These are simply a kettle with no lid and have a steam take off, usually permanent (no isolation valve) and run at very low pressures.
Usually they are fired by spirit, or in mo re recent years fuel tablets. They are lots of fun, very simple, very safe, pretty much impossible to get wrong and are as reliable as any highly engineered engine. For many, me included, pot boilers and simple engines were the way into the hobby.
Here is an example of a model pot boiler-
(Cant get it to post here- at end of post)
This a Mamod type boiler- the three connections are from the front- water filler cap, safety valve and steam take off.
These boilers are very inefficient, fuel hungry and poor steamers- BUT- they work, and well too. Water goes in- ĺ up the gauge glass (the sight glass in the brass casing on the end plate of the boiler), the fuel is lit and placed under the boiler and once steam is raised in a matter of seconds it starts to drive the engine- normally an oscillating engine (an engine that has no valve gear (the means by which steam admission to the cylinders is controlled) and the cylinders move on a pivot to negate the need for a connecting rod and giving ultimate simplicity)
These boilers can, and have been used in model boats, model buses, cars and fire engines and modified to power all manner of miniature vehicles, mill scenarios and steam workshops.
If you donít know about steam look on any internet auction site for an example, your local newspaper adís, local toy auctions etc- anywhere really, or even buy a new one, they arenít all that expensive- you will learn far more by having one of these fascinating and endearing hissing and fizzing little beasts than you ever will from any book.
Have a look here for more details of pot boiler models;www.forest-classics.co.uk/Mamod.htm
More details to follow.