Making A Model Steam Plant Diaorama Part 2

Part 2 – Running On Steam

In Part 1 I introduced the model steam plant I was making with my son, Alex, as a short holiday project.

Now, a good few weeks and a lot of work later, it’s running on steam and there’s a video here. Make sure to watch the pressure gauge in the top left!

General Comments on the Diorama

Burner Undersized

If you watched the boiler pressure gause in the above vide you’ll have seen how quickly the boiler pressure fell. Clearly the gas-fired burner (that came with the boiler is either a) undersized of b) not set up correctly. I’ve done quite a bit of investigating this and will report later. (Please join the Announcement List to be advised when I post the results.)

Other Coments

It’s a lot more advanced than the previous video when the engines were simply running on compressed air but this is still only a first stage – to get the engines running on steam.

There is a lot more planned for the future, like,

More detail to the engines, pipework and plant generally, like,
- Cylinder Drain Cocks
- Better arrangement of displacement lubricators
- Thermal insulation (cladding) to the steam pipes
- More steam pipe supports
Proper feed-water heater/condenser to rplace that vertical ‘hot well’ you see in the video
Mechanical feed pump (See below)
Cold water storage tank on a tower gravity feeding the ground level tank seem in the video
Additional gas fired burner to the boiler – to be replaced later with a conversion to coal firing, then,
Coal storage bunkers and a converyour velt to supply coal to the boiler
And so on…

Steam and Water System Schematic

Here is a simplified schematic diagram showing what I’m currently planning for the final steam and water system for the steam plant diorama:-

**Proposed Plantroom Steam and Water Schematic Diagram**

Mechanical Feedwater Pump

This is my response to a friend when discussing this diorama and his experience running his own engines:-

Note your comments on the large amount of condensate produced potentially.

This ties in with my calcs for condensate rate and Keith Appleton’s (Youtube) comment that he is ‘continuously working the hand feed pump’ to get water into the boiler.

I figured out that for my two engines (1″ and 5/8″ bore) running at ‘modest’ speed I’d need 5.6 l/hour of boiler feed water. (= condensate)

With my hand feed pump of 3/8″ bore I’d be needing one stroke per second!

Hence a mechanical feed pump is required. Ditto condensate pump.

Ideas For The Mechanical Feedwater Pump

Idea 1

This is a sketch I sent to my friend as a preliminary idea for a feedwater pump:-

Sketch of a Variable Stroke Feed Water Pump

And here are my answers in reponse to his question “”Why the complex water feed pump?”:-

I just hate the bypass type of feedpump as I have on the Showmans because of the inherent inefficiency. Whatever volume of water is pumped into the boiler, the power required to drive the pump remains the same. No reduction if less water is pumped into the boiler.

Not a practical issue, just poor engineering.

Firstly to avoid the efficiency described above. Secondly to add interest, as you say.

I could go for a reciprocating steam driven pump (no rotating parts) but according to Keith Appleton they are a) not easy to make and b) difficult to get working properly.

https://youtu.be/V0O7QkNK4yQ?si=nYE6KZm_w26CLveO

What I am suggesting probably has no real-life counterpart – so it’s going to be unusual if not unique. I like that.

Idea 1A

I came across this version on YouTube. It’s similar to my idea but much more neatly presented:-

Variable Stroke Pump Linkageby Lindsay Wilson

More and More Steam Plant Information, Ideas, Design and Construction

Well, that’s enough for this page. I have plenty more Steam Plant Information, Ideas, Design and Construction already developed and just waiting to be uploaded.

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