The Steamboating Forum

All,

Sorry for all the activity, but you guys know an awful lot. I have ordered all the recommended books and joined the associations, so hopefully I will be able to progress with all that info and not be such a pest.

I was reading the NWSS publication recommended by Artemis and noticed something that had also been recommended by Bart as to start up procedures. In both cases it talks about opening the drain valves on the cylinders to clear out any water condensed in the steam line and the cyclinder when you are starting up.

It makes sense and I saw folks at Lees Mills doing so when they were steaming up. My question is related more to the specific engine I am going to be using. On the locomobile engine there are no drain valves, nor do I see any provision in the cylinders proper for them. There is a plug in the steam chest that I believe was used for an oiler in the original design.

Any observations ? I have steam coming into the top of the steambox and exhaust coming out of each cylinder into a combined manifold. There do not appear to be any other openings save the plug in the steam chest.

jon

Condensate collects in the cylinders, steam pipes and valve chests during warmup, and compression of this liquid water is not possible, so it must be drained off during warmup. Normally drain valves are provided for this, however some engines do not require any action on the part of the operator. This is an advantage with simple engines having "D" type slide valves. The "D" slide valve is held against its seating surface by main steam pressure, and if pressure in the cylinder rises above this pressure, the "D" slide valve will lift off its seat. When the engine is turned over, and a slug of liquid water is pushed by the piston, the "D" type slide valve is lifted off its seat, and the water is carried away into the exhaust pipe. The condensate in the steam pipes and the valve chest travels out the same way, so the engine clears itself of condensate with the relief action of the "D" slide valves.

On an engine fitted with piston valves, this "self relieving" feature does not exist, so a separate set of drain valves are required. There are both manual and automatic drain valves, but that is the subject of another topic.

John,

A friend of mine has a 1902 Delora with a Locomobile engine, his has no cylinder drains as well. The way they start them is with the Stephenson lever in full cut off (center), open the throttle a bit, and the steam chest drain and allow the engine to warm up, and it does get hot fast. After everything is hot, then the engine is rocked CW and CCW slightly to start (not full rotations), this reversing/jogging expels any condensate out the exhaust and open steam chest drains. He suggested that I do this on the twin in my tug, as it is essentially the same config as the Locomobile engine, and it works great. I have both steamchest drains manifolded to one valve that exits through the hull, just let the hot steam flow through the steamchests for a few minutes, leave it open and then rock the engine, after about 2-3 rocks it's turning slowly on a small bit of throttle. This would not work on a compound, and not be very practical on a single simple. It is best to do this with around 20 psi boiler pressure, not enough pressure to hurt anything if it is done improperly.

Fred, the D-valve lifting off the face as well, that's a good point that had not occurred to me.

-Ron