Lubricator. The lubricator, one of the most essential locomotive
appliances, is usually supported by a bracket from the back head
of the boiler in convenient reach of the engineer. It may be a
two-, three-, or four-sight feed lubricator as the case demands,
the number of sight feeds indicating the number of lubricating
pipes supplied by the lubricator. For instance, a two-sight feed
lubricator has two pipes, one leading to each steam chest. A
triple-sight feed is used to supply oil to both steam chests and
also to the cylinder of the air pump. In using superheaters, it
has been found necessary to oil the cylinders as well as the
valves, hence the need of the four-sight feed lubricator. Fig.
96 shows sections of a well-known make of a triple-sight feed
lubricator. The names of the parts are as follows: 1. CONDENSER
15. REGULATING VALVES 2. FILLING PLUG 16. TOP CONNECTION 3. HAND
OILER 17. EQUALIZING PIPE 4. CHOKE PLUG or REDUCING PLUG 18. OIL
PIPE 5. TAILPIECE 19. WATER PIPE 6. DELIVERY NUT 20. SIGHT FEED
DRAI