Selection of Papers by L.D. Porta – Volume 1 – Tribology and Lubrication

Description

“Porta’s 1995 Tribology paper is the most complete account of steam tribology ever written and offers the steam movement a new level of understanding of lubrication and wear” [quoted from Joe Cliffe’s preface to the paper]. It should also be essential reading for everyone involved in new-build steam, and wise reading for anyone who is interested in how steam locomotives might be improved. Its revelations include:

• how David Wardale’s Red Devil ran 55,000 km with barely measurable valve liner wear and zero measurable ring wear;
• how to reduce steam leakage across piston valve heads to near-zero levels;
• how sensitive lubricants are to (surface) temperatures – e.g. evaporation increases 40% for every 20oC rise in temperature while “cracking” doubles with each 15oC rise;
• how surface temperatures vary along valve liners and how they can be reduced;
• why high temperature steam should NEVER be used to transport atomised lubricants, and why/how oil should be delivered directly onto rubbing surfaces – “between the rings” in the case of valves;
• how to improve streamlining of steam movements between valve and cylinder;
• how the performance of mechanical and condensing lubricators compare and how to get the best out of them;
• how technical advances achieved by diesel manufacturers can be applied to steam;
• why snifting valves, bypass valves and the like should not be used, and why drifting should be done in mid-gear;
• much much more.

This is the first of (at least) three volumes of papers by Livio Dante Porta’s technical papers that Chris Newman has transcribed and which ASTT plans to publish. This first volume focusses on tribology and lubrication and contains the following papers:

• Steam Engine Cylinder Tribology 1995 edition
• Steam Engine Cylinder Tribology 1975 edition*
• Cooling of Piston Valve Liners 1978*
• Mechanical Design of Piston Valves 1975 revised 1977*.

* These three papers dated between 1975 and 1978 were written for the guidance of David Wardale in his South African endeavours. The 1995 Tribology paper is an updated version of the original 1975 edition.

The four papers fill 250 black and white A4 pages.