BUCYRUS ERIE 50-B

STEAM SHOVEL

Part 12 - Boiler testing - by Alberto Celot

Before testing the boiler and final assembly, I designed and built a needle valve with fine adjustment.

Then I did several tests with different types of fuel, always related to diesel, and eventually found the ideal one; It is a fuel used for home heating stoves without a chimney, totally odourless and very pure.

I then installed the boiler, complete with all the accessories, in the test fixture and started the final tests. At power the burner is fed with the compressed air and then moves to steam when the pressure in the boiler is sufficiently high. When the burner began to be powered by steam, there were some problems: because the level of the

boiler water was a bit too high, a few drops of water got into the burner, causing intermittent extinction  the flame. I solved the problem by creating a steam outlet for burner placed at a higher level than the safety valves and shaped in such a way as to avoid as much as possible the capture of water droplets, as can be seen

the two following photos:

I made a coil to fit inside the combustion chamber which evaporates any drops pf water. I also replaced the ceramic coating with 6mm sheet.
On test the boiler and its accessories worked normally - apart from one injector which needed attention. The boiler pressure reached 6 bar in about 15 minutes, but it all depends on how you adjust the flame, which can be varied within a relatively wide range.

The adjustment of the flame depends on the pressure in the boiler, which may vary when withdrawing steam or filling water with the injectors; is therefore necessary to adjust it to the operating conditions. It was not for nothing that two people were needed in full size, a man at the boiler and lubrication and an operator to control levers!

There was no trace of smoke.

I disassembled the boiler from the temporary support and I reassembled everything on the frame of the revolving frame. On this occasion I decided to replace

the horizontal injector with one of the vertical type, and the simplest arrangement of the hoses to facilitate maintenance.

Here is a picture of the new piping arrangement:

Next came the construction of the cab sides.

To access the various controls, the roof and the two sides had to be removed; the solution I have adopted was to insert into the sides some small magnets, which have a sufficient force to hold the sides, well bonded to the metal frame but allowed  to detach with a small pressure. The roof is simply interlocked on top.

The sides are made using an epoxy glass laminate (the one used for printed circuit board) of 2 mm, with both sides coppered. Using a shaped blade I scored the lines that simulate the edges of the boards, while the flat bars which are bolted to the tables were made with a strip of brass into which were deep drawn the heads of the fake bolts. On the back I glued reinforcing beams. The doors are suspended on pulleys that run on a track, while the lower part has a containment guide.

Here are the photos of one of  the two sides and their backs:

And a closer look at one of the doors, and how the ‘bolt heads’ were pressed into the brass strip. The punch was made from a broken end mill.




































The final result after painting:
The plaques were made by high-resolution 3D printing.
Part one   part two   part three   part four   part five  part six  part seven  Part eight

part nine   part ten   part eleven  part twelve  Conclusion





 




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Editor - David Carpenter