firing up woes

[oldnorton]

Four jets of 0.55mm bore are suitable for a small 5 inch gauge 0-6-0, and four at 0.70mm for a larger 5inch 4-6-0

[runner42]

I have increased the size of the blast nozzle blower to 0.028".

At the other end i.e. the blower valve and tube I have pressurised to WP and opened the valve to see what effect this has of the blast of air coming from the 3 X drill no 57 holes. The results show an air blast which I would classify as moderate and not severe. Bearing in mind that the operation of the blower valve should be intitiated at 30 PSI, so at this pressure the air blast is at this pressure is less than moderate. 

blower valve_exposure by Brian Leach, on Flickr

Here is the blower valve (poor quality photo) and the other end where the pressure was applied.

blower valve1_exposure by Brian Leach, on Flickr.

The drawing of the blower valve shows the internal construction and the internal pathway for air or steam shown in red. 

blower valve by Brian Leach, on Flickr

The hole size for the valve seating is 1/16", so effectively the ultirmate pathway is only is 1/16" (0.0625") and not 3 x drill no 57 holes (3 X 0.043")
Comments please.

Brian


 

[Neale]

The drawing suggests that you could use separate nozzles instead. Would this be a way to try out different hole sizes? Asks a Black 5 builder who is a good year or two from this stage...

[oldnorton]

Separate nozzles always a good idea. Whether fixed or not they should be angled to send the airflow to a common point at the throat of the petticoat tube. Drilled vertically, the flow will miss.

[dhamblin]

You don't want the blower to be too powerful otherwise it will suck more than heat through from the fire. The draughting design i.e. the petticoat pipe shape, will make maximum use of the steam jets available.

Regards,

Dan

[runner42]

After putting everything back, I was faced with a new problem. The steam dome cover plate had a leak that I could not seal, no matter what methods of sealing was employed. The problem was due to the fact that the Australian boiler code required 5mm fixings and the land area using DY's measurements put the holes close to outside and insdes of the steam dome bolting face. I had to increase the land area to get a good seal. The initial sealing was OK for the 2xWP test. So I modified the steam dome cover by including an annulus affixed to the cover that extended into the steam dome. It worked.

Brian

[runner42]

After a three months layoff due to holidays, COVID and generally frustration by my lack of progress, I decided to revisit the blower issues associated with firing up. My initial thoughts are that the electric blower is inadequate for a 5" gauge locomotive and I decided to produce a bigger fan and run the 12V motor off a 12V battery supply, instead of 6v. This produced a frightening result in so much that the motor ran at an alarming speed and because the fabricated fan is not truely balanced, vibration was so violent that the fasteners began to shake loose. Also, the wiring at screwed junction began to glow. Running beyond 30 secs was impossible. The vacuum produced was 10 times better. I tried to Google the motor part number and the results were unsatisfactory in providing the designed RPM. At a guess it is 5000 RPM or more. My soultion is to insert a PWM speed controller in circuit so I can have some control. 

I have assumed that the ashpan front door is there to enable the ash to be removed, so apart from cleaning the ashpan the door remains closed. However, I have watched a video where it is said that this is a damper  and is also used to control the air entering the firebox. It is forward facing so running in a forward direction air is forced into the fire. Comments please.

With my renewed enthusiasn I hope I can make progress.

Brian

[runner42]

My setup is now assembled albeit temporary. The speed controller gives me control over the fan allowing it to operate over prolonged periods without self destructing.


Speed control by Brian Leach, on Flickr

fan by Brian Leach, on Flickr

This arrangement generates a good vacuum so no more problems in reaching operating pressure.

Brian

[dhamblin]

Well done Brian, another piece of the jigsaw falls into place. It can be quite satisfying this 'fettling' phase of a build.

Regards,

Dan

[runner42]

May 18, 2024 3:22:58 GMT runner42 said:

My setup is now assembled albeit temporary. The speed controller gives me control over the fan allowing it to operate over prolonged periods without self destructing.


Speed control by Brian Leach, on Flickr

fan by Brian Leach, on Flickr

This arrangement generates a good vacuum so no more problems in reaching operating pressure.

Brian

How wrong can I be. After, being sidetracked on a redesigned blower valve and a leak in the piston rod gland, I took the opportunity to utilise the electric blower to produce steam. Everything, appeared to be working OK but after some minutes running, the electric blower motor started to slow and eventually lock up. The reason was possible due to the fact that the blower motor became very hot due to heat generated by running and the fact that the heat from the fire's hot gasses made the blower assembly extra hot and caused temperature sensitive parts to alter their characteristics. 

The question is; based on the environment in which it is required to work what type of motor construction would operate continuously in temperatures experienced at the chimney and or what design consideration would be necessary to isolate the motor from the hot gasses. Would for example make the plate that the motor sits on a greater thermal mass and thereby be a useful heat sink. 

Electric Blowers aren't rocket science, so I am hopeful that the experience of others will put me in the right direction.


Brian  

[uuu]

I've always thought that the two parts of the blower stay separate, from a thermal point of view. Some little motors get really hot, and need to be lifted off with a cloth to avoid burning hands, and some bigger ones stay cool. The hot smoky end seems independent.

You could try running yours off the loco for a while and see if it still locks up.

Wilf

[nonort]

I suspect a bit of over engineering from the photos. The fan needs to be closer to the chimney plate no more than say a sixteenth of an inch you will ned some end float in the motor shaft to compensate for the expansion of the various components. The plates will buckle a little the fan will expand quiet a lot. My advice is to think Blacksmith not precision engineer.
All the best.

[JonL]

Roger had quite a good design of Blower which kept the fan away from the heat (a bernoulli style design maybe?).

[JonL]

I seem to be suffering something similar now.... once the needle is off the gauge stop its fine, but it can take me well over an hour to make that happen. However once she is away I can't stop her making steam! Such a frustrating problem.

[dhamblin]

Build up of soot on the fan blades?

Regards,

Dan

[uuu]

The latest batch of coal at IWMES seems a bit more reluctant to get going than previous lots. Then it goes well. But it seems to block the grate more quickly after a spell of running.

Perhaps you have some dud stuff, too.

Wilf

[chris vine]

I use charcoal soaked in paraffin as fire lighters.
Some people say the paraffin will cause soot in the tubes, but it doesn't seem to cause a problem for me.

You can keep adding a few lumps of coal and the paraffiny charcoal until the coal fire is really going nicely.

Hope that helps...
Chris.

[Boadicea]

Jul 21, 2024 15:11:56 GMT uuu said:

The latest batch of coal at IWMES seems a bit more reluctant to get going than previous lots. Then it goes well. But it seems to block the grate more quickly after a spell of running. Perhaps you have some dud stuff, too. Wilf

Wilf, funny you should say that. We are having the same issue - need to do loads more raking out - even the cleverer boys are saying the same. Loads more ash clogging up the bottom.
When you leave the fire alone, you suddenly find the gauge has dropped to 20psi.
I don't think it's a duff lot, it's all we can get.

All part of the stupidity policies whereby you don't mine our own, but import rubbish instead.
I'm talking about anthracite beans, not small nuts for bigger engines - supplies are getting really short of the latter.
At least we can still buy beans, even if you can only buy rubbish!

Then, of course there's the stuff which starts off as a waste product from olives and gathers up other things like coconut husk from the other side of the planet and makes something which look like coal. It's renewable, but whether it will burn is a secondary considertion.

Jul 21, 2024 15:17:21 GMT chris vine said:

I use charcoal soaked in paraffin as fire lighters.
Some people say the paraffin will cause soot in the tubes, but it doesn't seem to cause a problem for me.
You can keep adding a few lumps of coal and the paraffiny charcoal until the coal fire is really going nicely.
Hope that helps. Chris.

Agree Chris.

[oldnorton]

Yes, I have heard suggestions that recent (this year) deliveries of anthracite beans are not burning properly. So far, I have been running on two year old coal (anthracite beans in 25kg bags from the local coal merchant) that have been ok. But yes, I now have to rake the fire after one hour to shift a sticky ash that does not fall through, add more coal and run a full blower for a few minutes.

We can still get anthracite beans because the supply to domestic boilers is still permitted. But there are no more anthracite small nuts because these were for industrial boilers, which have all gone. This is what I have heard and it all makes sense to me. I would suspect that ALL the domestic supply of anthracite beans is coming from one place and it is not the Welsh quarry that used to supply them. So have we got a poor supply now rebagged by all the various local coal merchants? Signal Fuels is one supplier who might know what is going on.

Our club has a new supply of these anthracite beans and I will just have to join the experiment of seeing if they burn.

Sorry to the OP who is in Australia, this has nothing to do with his issues!

Norm

[jma1009]

Hi Brian,

For what it is worth here are my thoughts based on experience.

A decent electric blower fan ought to be able to get the water boiling and the safety valves lifting at working pressure on firstly charcoal soaked in paraffin (my preference is to use BBQ lighter fuel instead of paraffin) then charcoal alone. [It is/was a well known ‘trick’ in the UK IMLEC to reduce initial coal consumption].

So, from my perspective, you ought to be able to get to working pressure on just charcoal. So the quality of coal ought not initially come into the matter.

[The above IMLEC example is not what was my usual practice]

I found electric blowers very dependent on the voltage. 2 car batteries (can’t remember when in series or parallel) would make all the difference between getting steam up in 6 minutes compared to say 15 minutes!

The electric blower ought to be able to suck off the shovel a load of charcoal or small coal.

Try running your electric blower at 24 volts instead of 12 volts.

Cheers,
Julian