Draft

[Steam Engine Dan]

hi guys, i wanted to share these videos on steam locomotive draft made by grand canyon railroad employee eric hadder. i know we all have basic knowledge and understanding on steam locomotive draft. but i still thought this was worth sharing. it makes for good shop talk. part two covers the different types of blast nozzles the grand canyon railroad has used in their steam locomotives and the different results they have had with the different types of blast nozzles. enjoy

https://www.youtube.com/watch?v=7sj-OZ37RZQ

https://www.youtube.com/watch?v=xs7rwEVMT2o

Daniel

[JJG Koopmans]

It is a pity that the second video gives such a poor explanation of the improved draft of a Lempor.
This has little to do with whatever Dante Porta or Nigel Day stated, but has everything to do with the explanations of
Buckingham of 1913(!!) as treated in a proper text book in fluid dynamics.
Kind regards
Jos (and yes the second book shown was mine)

[STRR]

Jos, I agree with you. His explanation only covers about half of the subject. The other half being the "petticoat" or eductor portion of the system. While it is important to design/control the pressures/flows through the nozzle sitting in the smoke box. It is equally important to design the converging/diverging portion of the smoke stack to properly "seal" the smoke box and ensure the creation of the draft by "steam induction".

Modern nuclear powered submarines use steam for motive power. In order to make the most efficient use of the power created, vacuum is needed to extract the last amount of energy from the steam. Air ejectors are steam powered eductors used to create the vacuum initially, until the steam condensing maintains the vacuum in the condensing portion of the system. Then the air ejectors do exactly as their name implies: remove non-condensable gasses from the system. Every nuclear machinists mate is required to understand the concept and use of the dual nozzle device.