Water Hammer -- an interesting object lesson

Jamie Hall

I have as many of you know a very nice vapour steam system, works just fine.  One of the bits of radiation is a 20 foot long double fin iron tube convector -- steam comes in one end of the upper tub, travels along, turns down, returns and eventually out (total of 40 feet of fin tube).



So...



Was vacuuming the other day, and knocked the support out from under the far end of the unit, dropping it about half an inch -- but I didn't realise I'd done that.  Until Cedric fired up the next time, at which point I had the most amazing percussion section going in the room (iron fin tube has a nice ring to it).



Put the block back under the end, and all is silent again.



Who would have thought that half an inch in 20 feet would make that much difference?



Moral of the story: I, and others, have preached correct pitch more times than I can count.  We're right.