Reply To: Tests on Lempor Exhaust

[Chris Corney]

I think I’m correct in saying that the smokebox pressure returned to “atmospheric” between each “chuff”.
A while ago we had a discussion about pulsating smokebox pressure. My background is as an electrical engineer, and we are working with pulsating quantities all the time (i.e. ac). Adapting a method from this area, it occurred to me that there might be some advantage in having a double chimney with one being a Kylchap and the other being a Lempor. For each “chuff”, due to the difference in steam operating velocities, it would take slightly longer for the Lempor to reach “terminal velocity”, by probably a few tens of milliseconds, than the Kylchap and therefore the pulses of suction from the two chimneys would be slightly out of step. The overall magnitude of the oscillation would be reduced, compared with an equivalent double Kylchap or double Lempor. Following the discussion on the “Kylchap” thread I’m now thinking that under these circumstances the Lempor could be acting as a more efficient pump, if pulling against the vacuum which has just been created by the Kylchap.

Obviously this would require a lot of work to optimize!

Does it make any sense?