OIL AND STEAM

Hokitika Guardian, 11 May 1929, Page 7

OIL AND STEAM

USE OF LUBRICANTS. That the research work of the chemist is of great importance to the engineer was demonstrated in an interesting paper on the “Theory and Practice of Steam Cylinder Lubrication,” read by Mr W. Sommerville before members of the Wellington branch of the New Zealand Institute of Marine Engineers Inst week. Among those present were representatives of several oil companies. In dealing with the problems to bo faced, the author said that among tlu operating condition that a cylinder lubricating oil had to meet were steam pressure and temperature, velocity moisture in the steam, the degree of . superheat, priming or framing, the point of introduction, boiler compounds and the use, if any, to be made of the exhaust steam. Discussing the effect of steam temperature on the viscosity of cylinder oils, he remarked that temperature and velocity affected atomisation to a marked extent. Thus, the higher the temperature and velocity tne more readily would a heavy-bodied oil be atomised due to the reduction in viscosity 7 at the temperature of operation. ffhe practice or using a straight mineral oil to lubricate we! steam was customary only where the presence of a fatty oil in the exhaust steam was objectionable. Where a compounded oil was used an emulsion was developed by the moisture in the steam reacting with the fatty comopnont. The lubricating film thus had a greater affinity for the cylinder wails and other wearing surfaces and became highly resistant to the washing action of the water in the steam. The amount of compound should be just sufficient to maintain a film on the cylinder walls. The objectionable features of emulsified oils were outlined. The lubricating requirements of specific types of engines and the influence of valve designs were discussed in detail. Dealing with types of lubricants the author said that steam cylinder oils must be of comparatively heavy body, and have a particularly adhesive characteristic. The most efficient way of getting lubricating oil to all desired points was to make use of the steam itself and the degree of success in the atomisation of the oil would control both the efficiency of the lubrication and the quantity necessary. The methods of the application of lubricrants in steam cylinders were described, stress being laid on the importance of the point of application in force-feed lubrication to secure the maximum of atomisation of the oil. The efficiency of lubrication could be judged by the film of oil on the piston rad, the amount of oil in the condensate, and ; the action of the valves. An interesting discussion followed the reading of the paper, for which Mr Sommerville was accorded a vote of thanks.