. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . ubrication. Valve oil in service, fromthe time it leaves the choke plug at lubri-cator until taken up by the steam is inthe form of an emulsion. The steam at atemperature of nearly 400, becomessaturated with this oil in suspension, we note that as steam is exhausted fromthe high pressure cylinder of a com-pound at a higher pressure and conse-quently with greater temperature thanin the simple engine. It follows that lesscondensation takes place in the highpressure cylinder, hence less oil is l
. Railway and locomotive engineering : a practical journal of railway motive power and rolling stock . ubrication. Valve oil in service, fromthe time it leaves the choke plug at lubri-cator until taken up by the steam is inthe form of an emulsion. The steam at atemperature of nearly 400, becomessaturated with this oil in suspension, we note that as steam is exhausted fromthe high pressure cylinder of a com-pound at a higher pressure and conse-quently with greater temperature thanin the simple engine. It follows that lesscondensation takes place in the highpressure cylinder, hence less oil is lefton the walls of this cylinder. The greaterpart of the oil passes over into the lowpressure cylinder, and a portion of itpasses out at the exhaust. This can bereadily shown by examining the condi-tions which exist in any power plantusing a condensing engine. As a help to the fuller considerationof this comparison let me point out thatin the 22x30 in. engine, at an 8 in. cut-off, we have 1, cu. ft. of steam atboiler pressure used per mile, expandedto 4, cu. ft., which gives us 475 MEETING OF BOARD OI- ENGLISH DIRECTORS. only a few degrees below the ;point of the oil; steam enters the cylinderand comes in contact with a surfacecooled by the expansion and exhaust ofthe previous stroke; condensation takesplace and a portion of the oil thus heldin the steam is deposited upon the wallsof the cylinder. Those portions whichcontain the greater thickness of metaland consequently retain the greateramount of heat, receive the lesser por-tion of oil, notably the upper part ofcylinder and the piston head. A portionof this oil must necessarily pass away inthe drip from cylinder cocks and otheravenues of escaping steam, so that wehave only a portion of our drop for ac-tual service, how much I know not. I■cannot see where, according to thefigures shown, we have any to temperature of steam is governedb} the pressure under which it is used,and as
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