[modeleng] Re: Blowing down

Gents,

Now, back to the proper way to blow down.  On full scale locomotives this is
done while traveling along open trackwork and not stationary in crowded
yards as we do with our models.  This is good for two reasons, one safety
for other trainmen and because the water and sludge between the firebox
walls is somewhat agitated by the motion of the engine while traveling.
Preferred blowdown method seems to be several quick openings of a few
seconds duration as the sudden release of pressure causes the water in the
vicinity of the valve to become agitated and this aids in removing sediment.
As I cannot blow down while traveling because of the arrangement of the
valve handles on my lokies, I have to do all of my blows while in the
steaming bays and several short duration blasts while pressure is high would
probably be best.  After the boiler has cooled somewhat and running for the
day is over with, then a prolonged blowdown at 30psig until boiler is empty
should be done.  The boiler instructions for the large 150 hp 15psig dry
kiln boiler we had at the sawmill mentioned several short blows as being the
best, for the reason I just stated, agitation.  Actually, it seemed that I
had my hand on one of the four blowdowns on that 15hp boiler all day long as
I made it a habit of opening one of the valves every time I passed in the
vicinity of it.  The water here in Troy has a very high mineral content of
way over 200ppm, around 250 as I remember it, and it seemed that no matter
how many times I blew that danged boiler down, the mineral content was still
too high so I just did the best I could and hoped the boiler chemicals kept
everything clean.

Jesse in West Tennessee

MODEL ENGINEERING DISCUSSION LIST.

To UNSUBSCRIBE from this list, send a blank email to, 
modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.

Other related posts: