Emulsion Tendencies of Lubricating Oils

Federal Test Method 3021.5 is intended for use in the determination of the emulsifying tendencies of lubricating oils. The test  consists  of  placing  40 ml each  of the  test  oil  and  of  either  distilled  water or  a one  per cent  salt solution in  a 100 ml graduated cylinder.  The  cylinder  is  then  placed in  a  bath  regulated to  either 130 0r  180 degree F and  the  contents  stirred with  a paddle  at  1500 rpm  for  5  minutes. Following this, while  still  maintaining  the  cylinder at  the  test  temperature , the time  required for  the  emulsion to  break  is  noted.

In  the  case  of  circulating  oils where  the  lubricant may  become  contaminated with   water, a firm emulsion  would  interfere  with  both  circulation and  lubrication. Therefore, under such  conditions  of  operation,  oils  which  show  little  tendency  to  emulsify  are  desirable.

Dripfeed Gear Lubrication

Dripfeed application of gear oils may be considered semi-automatic in that it is adjustable to a certain degree. The feed for the oil in this case may be by gravity or even by circulation if the stream in the latter instance can be throttled down sufficiently. In the first case a container can be filled by hand or even a small drum can be connected with piping ending in a valve or cock to permit adjustment of the feed. Here, as the amount of oil in the container becomes less, the feed will decrease. Where such a feed is partly mechanical, the oil will come either from a storage tank to which a pump has delivered it or directly from a circulating line. In either case the amount of used can be calibrated.

While dripfeed can be applied to enclosed gearing it is more often used on open gearing. Here it is applicable to softer types of gear oils including cut back types. This is more desirable method of lubricating open gears than the methods previously mentioned. Also, in case cut back gear oil is used, any vapor from the same will escape slowly and hence will be less of a hazard than if the mixture were sprayed on. Further, there are fewer tendencies to over lubricate by a drip method than with other methods of hand application. Therefore, there is a consequent reduction in waste and poor housekeeping.