Jens, your command of English is far better than my command of your native language, but to answer what I think you have asked :-
A given content of water in any boiler is capable of generating a certain volume of steam. The way to increase the volume of steam is to feed the boiler while it is operating, with more water to compensate for that which is evaporated. You do this by adding a boiler feed pump which can be operated manually or coupled to the engine but needs to be controlled within limits so that not too much OR too little is fed in.
Vapour (Steam) pressure is controlled by burner heat and also heating surface which are determined by the evaporative rate of a boiler, but the design of the boiler controls the efficiency of the heating surface.
DON’T stop asking questions, but it will become a lot clearer when you see the book mentioned. K.N. gives worked examples of how to “Size” a boiler for the engines requirements and also the different DESIGNS of boiler for different applications.
There are times when you want to tear your hair out with the course you have chosen to amuse yourself with, but it IS worth it in the end.
Regards Ian.
Edited By Circlip on 27/12/2009 10:52:00