Automatic boiler water control pump

[mjt60a]

I saw one of those at the Kew Bridge show a couple of weeks ago, wish I'd taken a photo now....

[NMRC]

Hi All

The boiler is quite large being about 9" x 6" x 6" I guess.

Being ancient I do not want to start interfering with it beyond changing fittings.
There is nowhere to fit a gauge glass and anyway it would be below deck so pretty pointless when it's on the water.
Hence the idea of using the automatic water control system has a twin benefit. It will replenish the water if it gets too low and will let me see the state of play by which of the 3 diodes are lit.
That is if I can position them somewhere in view and they are bright enough.

Having fitted the pressure gauge  I thought I would test it before going any further.
No such luck!
It gets in the way of the old rechargeable gas cylinder that I have at present to put below deck. It's awkward because the gauge is positioned so that it can be seen through a deck cabin porthole one of six provided to supply the airflow for combustion.
Not a great problem it just means I have to complete the pipework for the new disposable can system of valve and regulator and fit new mountings first.
I hope to be able to use the original gas jet although it looks as though it might need to go into the boiler combustion chamber at a slight angle to miss the bottom of the canister.
Who said problems were just opportunities.
I would not mind the occasional opportunity that was not a problem.

Regards

NMRC
    

[NMRC]

Hi All

Well that took a lot longer than I thought !
I ended up having to make the 2 nipples and both nuts for my pipe connections from the regulator to the nozzle.
Then the canister needed to be mounted which was a bit of a saga.
I tried using various bits of wood to give me an idea of level  but eventually thought of using plasticine. From that I could see the height I had to play with. Basically none but it identified it  required a slight tilt forward as well as being just slightly to one side for the nozzle and pipework to fit. Hopefully its position in the bottom of the hull and straddling the centre line will not materially effect stability.
A flat base of balsa and a thin piece of ply 1/2" above it with a cut out for the can to sit in and finally its ready for a test.
I did not put more than a  half inch of water over the top of the combustion chamber and was surprised how quickly it  got up to pressure.
So now I have a working and legal source of gas firing, a working pressure gauge, and know that 12psi is the maximum pressure in the boiler.
Now I need to think about whether my thoughts on using a  peristaltic pump is still viable!
Regards

NMRC
 

[steamboatmodel]

12psi is a very low boiler pressure. "Now I need to think about whether my thoughts on using a  peristaltic pump is still viable!" I had to look up peristaltic pump, I knew them as tube or hose pumps, a tube pump will work well up to 100psi higher than that you have to go to a hose pump. We used a tube pump for adding boiler treatment to a heating system boiler running at 80psi with no problems.
Regards,
Gerald.

[FlashTwo]

Hi,

I have made several electric driven pumps which deliver up to 70cc/min in the pressure range of zero to 100psi to my flash steam boiler supplying steam to a Stuart D10.

The motor is an MFA with 100:1 gearbox, 12v (Maplin N03BQ) driving a ram 1/4 inch dia by 1 inch stroke and with simple 3/16 inch stainless steel ball valves and no o-rings.

The motor is powered via an Electronic Speed Controller ( bit of a misnomer, since it dosn't control the speed) which uses the standard PWM from the radio receiver.

To make the flow independant of the boiler pressure, the ram stroke is detected by an electronic pickup which is connected to a proper speed controller which adjusts the PWM to the ESC.

The desired flow can be set and the pump will give that flow independant of the pressure.

Here is a photo showing the pump under development.

Ian

[Bernhard]

hi.......Maby Regner have something you can use

http://www.youtube.com/watch?v=Loy2qdXYaCk

Regards Bernhard   
or this
http://www.home.earthlink.net/~bfindus/index.html 

[NMRC]

Hi All, and thanks for your input Bernnard.
Sorry I have not kept in touch.
I did write a great big missive but on deciding to add a smiley to it,
lost the lot which rather put me off for a while.
My efforts to complete the project hit a few walls.
the main one was the excessive weight of the battery I thought was needed to run the pump. It has to be fitted behind the engine as the only viable space, and unbalanced things. Hence my interest in Bernnard's last post which the second web address shows a rather compact pump unit and pump combination. Definitely worthy of further enquiry.
Anyway at this point in time I have made up the electronics. But without the second stage to drive the rc servo, just fitting a suitable transistor to act as a power switch for the, at present, none existing electric pump.
So I have a boiler water level senser, a box of electronic gubbins, a 9 volt battery( smoke detector size) and a mounting for the switch and two ultrabright LED's which are positioned to align with 2 windows of the rear deck room.
This is not the final fit but still gives a lot more confidence to put her on the water. 
She will be on the Northolt Model Railway Club stand at Alexander Palace London Model Engineering Exhibition this weekend so if your going come and have a chat

NMRC