Odor Control Agents

In general there has been no apparent  attempt  to cover up the odors  of gear  oils  which  arise  from EP  additives. Occasionally pine oil or pine tar will be detected in lubricants designed for exposed gears. Sulfur  compounds  perhaps  have  the most  disagreeable  odor  of any additives  and  consequently  Jonach^46  suggested  treating  such  agents  with  lead  peroxide  to  react  with  any  free hydrogen  sulfide  which might  be  present.

Fog or Mist Application of Gear Oils

Airborne oil mist or fog is being used to advantage in the lubrication of gear sets. The fog, consisting of oil atomized by compressed air into particles in the order of 2 microns in size, can be carried in pipes for long distances. At the point of application these will have to be reclassified to larger particles so that they will wet a metal surface. The air carrier must be vented from the lubricated part and is said to carry away heat. However, perhaps the heat dissipated will not be as great as in cases where gear oils splash or flow over gear sets.

The oil is used on a once through basis; consequently, clean, unoxidized oil is applied continuously. The amount of lubricant used is quite low, and the gears expend no energy in overcoming fluid friction of gear oils. With such a system, gear boxes are under some pressure; hence, no contaminants, such as dust, will enter.

Fog lubrication is only practical where sufficient points for lubrication justify a centralized system or where compressed air is available for use with a few points. The latter reason, therefore, probably rules out such systems in the case of aircraft and vehicles. If properly  adjusted, definite amounts  of oil  can be applied by  fog, and the system  requires  little  attention,  provided  there  are no air failures.