[TheForge] heavy metal math/c frame press

[John Husvar]

xlch58@swbell.net wrote:
> Steam is a gas, not a liquid, even saturated or super saturated  steam.  
> Gases can be compressed and can carry a lot of energy.  Water cutting 
> jets are an entirely different animal, they have extremely high volume 
> high pressure pumps not really comporable at all to ordinary hydraulic 
> systems.
>


Deja-vu all over again. :)

I recall this discussion going on for a time a while back too.

True, there are some pretty dangerous hydraulic systems out in the 
world. I worked on one that could maintain 5000 psig through a blown 
flange gasket on a 1-1/2 inch line, but (and it's a pretty big but) that 
system was driven by 4 (count 'em -- 4)  100 HP motors, driving 8 
big-ass Vickers Angle-Head pumps. (Pumped out about 50 gallons of oil 
before the automatic cutouts functioned.) I wouldn't have wanted to be 
in that pump room, close to that joint, when it blew.

That was the lower -powered, lower-pressure, system in that plant. The 
big stuff maxed at just under 10,000 psig with comparable flow.

What size system is any of us likely to use, a couple horsepower and 
maybe 5-6 gpm flow?

The chance of any of us having to worry about a pipe burst of dangerous 
intensity is vanishingly small.

The worst any of us is likely to experience is a blowout that lasts 
milliseconds rather than a second or two. It pays to be careful, but 
paranoid might be a bit far.

I'd think placing a removable sheet metal guard around fittings and 
hoses, maybe having a low-pressure cutoff in the pump circuit, and 
keeping a fire extinguisher at hand would more than adequately protect 
us and our shops. Any major line failure is most likely to produce a few 
ounces of oil, not gallons, and lose pressure almost instantaneously.`

Andy's point about small, misting leaks is well taken, however. Such 
could inject enough fluid under one's skin to create a very troublesome 
medical problem or could cut one -- and also inject the oil. They could 
also create a fire hazard.

In the Darn, Now _That'd_ Really Be Impressive If I Wasn't Scared 
Witless Dept: We had a flexible hose, on that machine I mentioned above, 
pop a leak under full load. It sprayed enough oil onto the 6-foot-tall, 
2300-degree steel billet in the machine at the time to turn that 
30-foot-tall press into a really bright Christmas candle.

The guys working the press at the time were all too familiar with that 
peculiar CRACK, POP, HISSSSSS sound and were fifty feet away before the 
fire got going. :)

The fire-suppression system worked just fine, so we didn't have to 
replace too much.

John

PS. The system log on the controller console showed the press operator 
had hit the emergency stop and fire-suppression buttons ten milliseconds 
_before_ the automatics tripped. I'd call that mildly startled at least. :)

-- 
Life is not a journey to the grave with the intention of
arriving safely in one pretty and well-preserved piece.
One should rather skid in broadside, thoroughly used up,
totally worn out, and loudly proclaiming -- "WOW!  WHAT A RIDE!"