More from Nigel:

Nigel
Would it be a problem to replace the the blast pipe stand with 100 mm (4inch) Nominal bore pipe parrallel in its length and use a standard 20mm thick slip on flange and a blank suitably machined on which to mount the nozzles?
My Son has redrawn the drawings to the latest information but has yet to dimension them.

A couple of other questions.
If the boiler pressure is increased from 150PSI to its registered Boiler Pressure of 165 PSI will it change the calculations?
The cylinder covers havn't been off for a while and I can find no records to show the bores have been checked recently.
I guess I should wip them off.
My Son also has a question.
If a 100mm NB pipe was used for the blast pipe stand and a blank flange used to mount the nozzles would it be possible to mill recesses in the flange to accept the nozzles?

This is the coolest thread on RyPN in a long time...

I have no concern on how you make the stand pipe. Its what you want. In its method of construction it can be of help as either you fix the stand pipe and alighn the chimney to the pipe or you fix the chimney and make the pipe to suit alignment. The nozzles need a flange of 3.6 inch bore and raised lip to be mounted on. What shape or size and pitich of holes is up to you. I recoment at least 12 mm bolts or bigger 4 off. I dont see the reason for milling recesses for the nozzles? More instructions will follow and make sence of what is already explianed.

That small change in boiler pressure will make no diference.
I imagine its not to big a job to check the bores of the cyliners so I agree its worth checking.

More from Nigel - apologies for the difference in sizes...





I agree - great stuff on this thread! Wayyyy better than another "what's your favorite steam locomotive" or "Strasburg should restore #1234!"

Tim

Today was work day on the Fowler and the Blacksmiths Hammer.
I was going to fit the eccentric rods but the machinist who turned the new pins hardened them without putting pin holes in them, bugger any how I got the post holes for the forge shed boxed up read to pour concrete.

Nigel more dimensions for you.
The Blower ring I.D is 0.675" O.D. - 0.895" x 11 -0.125" diameter holes.
Cylinder Diameters are 11.0625"
The Area of the modified Hulson firebars air gaps is about 243 square inches.
Having a look at the Blast Pipe stand I found that it had 2 x 0.625" Tapped holes in the back of it which faced the tubeplate. I wonder what they were for? I would not have known they were there if I had not decided to have a good look at the pipe.
I have ordered hollow bar 55mm x 30mm actual O.D. is 57.1mm and 26mm I,D.

Yes we are very fortunate that Nigel has chosen to bless up with his knowledge on exhaust systems its more than I ever hoped for. All I have to offer is what I have observed operating many different types of boilers over 47 years.
However I do have a pretty good digital library including Suggested Unit Course For Locomotive Firing, by the University of the State of New York State Education Department. Ask me, I might have it to share.

Just a few combustion considerations.
A few BTU calculations as to how many BTUs can you get out of 6 square feet of grate area. Especially trying to burn 30% worthless per pound coal with only 9500 BTU per lb heat content.
Assumptions are 75% cutoff, 48" dia drivers, 5.7 miles per hour, 127 psi mean steam pressure and a generous 80% thermal efficiency.

Note that about 14 lbs of air are required for each lb of coal.

The boiler that I designed, fabricated and welded on Maui for the Kahului Railroad #1 (Baldwin 1882) also has 6 sq ft of grate area. However, only 58 1.5"OD tubes, 6' 8" long and a 28" diameter barrel. Cylinders are 8" x 12".



Fig 24 is copied from "A Study of the Locomotive Boiler" by Lawford Fry published in 1924.

I am pleased people are finding it intresting. I thank Stephen and Tim for putting the pictures up. Not much more to explain.

I hope the instructions on how to mill the nozzles are now clear. The dimention across the base which needs checking is 44.25mm thus giving a point at the tip where all 4 nozzles meet at the centre. In a day or so I will do another drawring to ilustrate that and have done the blower calculation. I know already that there are to many holes in the blower ring and thus the velocity out of them is to low to create a good draught.

The last three photos show the milling of the nozzle flats and asembly of the nozzles. I have a few more to come espeshaly for the finishing of the welding and streamlining of the flange- nozzle area.

Thank you for the combustion coments , intresting but for now I am going to limit my coments to the draughting. Certainly we will have the ability to shift the air for such coal.

Great stuff -thank you, Nigel!

What is that bar across the smokebox of the Fowler? Was there a table and netting or a means to deflect the gases inside the smokebox?

If its the bar across the smokebox door, its the door locking bar.
If its the tube that goes halfway and centrally across the smokebox its a tube to connect a manometer to test smokebox vacuum.
The loco has no plates or baffles.

The two last pictures to come are of Grand Canyon and Welshpool. The Welshpool one shows a visable lempor and a hidden lempor.

I have now given Dennis allmost everything he needs to build the Lempor for his loco.

Later I will show the test gear. I use the absolute basics of pipes and gauges. John, Matt, and Dave at WRRC know more about electronic testing than I do. I to have great respect aslo for what they have done in the industry.

Mr Austin thank you for you contribution. Its intresting to see the difrence in the two boilers with difering proportions. You boiler has the ability to slow burn poor fuels but at lower total evaporative rates due to the limmited gas flow area of the tube bundle. The two chimneys would have major difreces in size and proportions.