23. Displacement Lubricators
1. This is an “inline” lubricator fitted to single cylinder slide valve engines. It is not adjustable.
2. This is an adjustable lubricator fitted to twin cylinder slide valve engines. It has a valve that allows adjustment of the rate of oil usage. It should be adjusted to use about one fill of oil to every 15-20 minute run of the engine.
3. This is an “inline” lubricator fitted to oscillating engines. It is not adjustable. The valve attached is used for manual control of the steam supply only.
A displacement lubricator works by passing the steam input to the engine over the surface of a small bath of steam oil. The steam gathers a small amount of oil, carrying it on to the internals of the engine, and exchanges it for a small amount of condensate. The condensate sinks to the bottom of the lubricator and the oil column moves up to maintain a constant oil level for extraction by the steam flow.
The oil is added through a manual nut on top of the lubricator and the condensate is drained through a drain valve on the bottom.
The lubricator should be drained of condensate at the end of each run and topped up with steam oil at the beginning of each run. To drain place a small cup under the drain valve and undo the nut a little. Any condensate will drain as a whitish liquid. This works better if the oiler is still warm.
Specially formulated oil, International Grade 460, for lubrication of internal components of a steam engine. (See Guide 22.)