In Tubal Cain’s book – “Simple Model Steam Engines” – vol. 1, he publishes a build/plan of a steam driven crane (Hercules).
In the build, TC publishes a plan for a steam control vlave/lubricator. This, he acknowledges, is a re-print of an original idea by LBSC and has “worked perfectly for 25 years”!
I am thinking of utilising this design in a simple steam plant which I am building.
I do not understand how this lubricator function works.
The stop valve is straightforward – a horizontal, threaded needle valve controling the steam entry point.
The lubricator is an oil reservoir sitting atop the main valve body, in the centre, opposite the steam exit point (downwards). The oil reservoir is capped (no breather hole), and the oil exits the reservoir via a tiny hole (number 70 drill), straight across the needle valve spindle and thus into the outlet opening. This hole is not blocked in any way by the needle valve – i.e. it is always going to allow oil to escape.
I am familiar with the principle of the displacement type lubricator, where the oil is displaced upwards from the reservoir by the effect of the entry steam condensing, but this lubricator seems to work the opposite way round!
What is to stop the oil continually trickling out, whether or not steam is passing that un-controlled tiny hole?