How to compute size boiler needed?

[Jack3M]

How does one go about sizing a boiler to the steam plant? For example just to run a Twin Victoria.....1" bore, 1" stroke.... (two cyls).
Add in a duplex pump that is two cyls, 5/8 bore x 1/2 stroke?

Got a feeling I am opening a can of worms I may not want to deal with.

 

[vederstein]

What pressure are you wanting to run? What RPM or cylinder strokes per minute? How much reserve minutes of run time do you want?

Water expands about 1600 times it's volume when going to steam. It's been a long time since I've looked and worked with steam tables, but run some simple calculations of steam flow, then double it to be sure instead of doing real thermodynamics calculations.

Also, you'll need to work out how much heating capacity you'll need. Most of the energy converting water to steam is in the latent heat of vaporization.

Your simple question is really very difficult. I built four boilers with varying levels of failure until I got one that will actually power my PMR 5CI and develop real power.

I'm sure someone out there can recommend some books or reference you to some existing designs.

I'm not giving you much of an answer, but unfortunately you haven't supplied much input either.

Good luck.

...Ved.

 

[vederstein]

Ok,

It's been a long time since I've done these calculations, so I make no guarantee they are correct. But referencing the attached spreadsheet you'll need:


Water Consumption: 1.56 gal/hr to run your engine 800 rpm at a pressure of 50 psi.
You'll need 4.1 kilowatts of heat to produce that steam.



...Ved.

View attachment Heat Calcs.xls

 

[Jack3M]

What you have done though is show me more about what I need to know to ask.