My name has been mentioned once or twice in this discussion, so below I
reproduce an FAQ I published some time ago:-
The purpose of the lubricator, (and I include this for those who are new to
steam locomotives), is to add oil to the steam feed and form a lubricating
film between the sliding parts of the cylinders and steam chest. There are
two principal types of lubricator used on model steam locomotives.
1. Mechanical, where a pump is driven by the motion of the locomotive.
These are more normal on the larger "ride-behind" gauges and uncommon, but
not unknown, in Gauge 1.
2. Displacement, where steam is introduced into the top of a sealed
container containing oil, condenses into water which, being denser, sinks to
the bottom displacing oil as it does so.
Displacement lubricators may then be further sub-divided:-
a) In-Line. The steam pipe passes through the lubricator on its way from
regulator (throttle) to the cylinders. A small hole in the pipe allows
steam to escape into the lubricator and the displaced oil to enter the steam
line. This type is often located in the cab, which means that the oil has
to pass through any steam drying or superheating pipes on its way to the
cylinders, which may cause carbonisation and eventual blocking and failure
of the steam pipe.
b) Dead-Leg. A small diameter pipe is teed into the main steam pipe or the
steamchest, its other end terminating inside the lubricator. Its action is
otherwise the same as the in-line type. The dead-leg has many advantages of
which the principal one is that it can be mounted downstream of the
superheater, close to the cylinders. It is also much easier to fit some
form of needle regulator to adjust the oil delivery. There are those who
claim that it cannot possibly work. (Aerodynamicists have proved that the
bumble-bee cannot possibly fly. The bumble-bee however, having no knowledge
of science, just carries on flying.) In fact, the constantly varying
pressure in the steamchest whilst the loco in in motion causes a pumping
action allowing the alternate passage of steam an oil, in opposite
directions, down the same pipe. ("Alternate" is used in it's Britspeak
meaning of "one and then the other and so on".) For it to work, there must
be space in the top of the lubricator for the steam to compress and expand
and there must be NO sump in the pipe where condensate may collect.
c) Parallel-Feed (for want of a better name.) A variation on the In-Line,
where a separate feed is taken from the regulator, via a metering valve, to
the lubricator. The outlet pipe bypasses any superheater and is fed
directly to the steamchest. Although more complicated to make, this is
probably the most effective as oil is only delivered when the regulator is
open, and the flow may be adjusted as the loco becomes run in and needs less
oil, resulting in a cleaner engine.
Peter Foley wrote:
> A little hole in the end of the pipe is better than a big one - Again
> quoting Mike Chaney (this is a foggy memory hear, wish he were here to
make
> sure I get it right) a No.50 drill is about perfect.
I'm here, Peter - just lurking, mostly.
The size of the hole is not important - what seems to matter is the steam
space above the oil and the volume of the steamchest (or its equivalent), as
these determine the extent of the pumping action. In both cases, the larger
they are, the more oil you get. In my lubricators (Mamod-Mod, Kitten, Hero,
Catatonk 24T Shay and 14T Heisler), the filler cap is hollowed out to give
the optimum conditions.
In another post, Kevin Strong wrote:-
> What you describe sounds a lot like the lubricator that Mike Chaney
> designed for the Mamod/Jane/Creekside, and other similar if not
> identical locomotives.
I know nothing of the Creekside, but the "designer" of the Jane phoned once
me and spent about 10 minutes telling me all the things he had altered so
that the Jane lubricator could not be called a copy of my design. I have no
idea why he called. Perhaps he felt guilty - silly twit! Incidentally,
the Jane meths burner works better if you lower it about 1/8" to give the
flames a bit more room to burn - he didn't copy that from me either!
[rant mode off]
> I have one installed on my Creekside locomotive.
> Unfortunately, I don't get good enough runs out of her to tell one way
> or another the extent to which it's working. I do get a good amount of
> oil on the cylinder face plates, so I can only assume it's getting some,
> but the amount of condensate I get out of the drain plug is minimal or
> nonexistant. This could have something to do with the "S" curve in the
> supply pipe that I had to put in to place the lubricator.
You could be right. The pipe may go "up and over" but never "down and
under" an obstruction. As I wrote in the FAQ, water will collect in the dip
and prevent the oil from passing.
Mike
http://www.mikechaney.fsnet.co.uk
