400 



FARM MOTORS 



will force the oil into the steam pipe against this pres- 

 sure. There are several makes of lubricators on the 

 market. Fig. 279 shows the principle of nearly all of 

 them. This lubricator is so arranged that the steam 

 condenses in the small pipe of the lubricator and forms 

 a greater pressure on one side of the oil than on the 

 other. This forces the oil from the valve to the steam 



pipe. To fill the lubri- 

 cator, the cocks from 

 the steam pipe should be 

 shut off so no pressure 

 can be let in ; then the 

 small cock at the bottom 

 of the lubricator should 

 be opened and the con- 

 densed water let out. 

 When oil commences to 

 come instead of water 

 the lubricator has been 

 drained enough. The cock can then be closed and the 

 cap on top taken off and the oil poured in. Several 

 makes of oil pumps now on the market are to take the 

 place of the lubricator. They are actuated by a lever 

 and arm from the crosshead. These pumps are more 

 positive than lubricators in their action and not as likely 

 to fail to operate. The only defect in this form of lubri- 

 cation is that very few pumps have a sight feed or a 

 glass which will tell how much oil is in the vessel that 

 contains it; thus it is hard to tell whether the pump is 

 full or empty. 



FIG. 279 CYLINDER LUBRICATOR 



