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Hammer Time

Tony Conner
Tony Conner Member Posts: 549
in THE MAIN WALL
Check out this link for some pretty impressive pictures of valves in big steam systems that failed under water hammer conditions.

http://www.kirsner.org/pages/forensicResAlt.html

Comments

  • Unknown
    Unknown Member
    Stunning!

    Thanks, Tony.

    Noel
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Water never ceases to amaze me with its properties, necessity and power.

  • Tony Conner
    Tony Conner Member Posts: 549
    The Pictures...

    ... entitled "Ruptured 8" Cast Iron Valve", and "Groundwater In Downstream Pit". Bring back some memories. I never actually saw anything blow out, but I spent about 12 years working for an operation with manholes just exactly like that. The worst waterhammer I was actually involved with was a 3" valve on a 10 PSIG line. I was standing on the curb, looking down the manhole while another guy just cracked that valve (and I mean JUST), and KA-POW, it was just like a rifle shot down than manhole. We didn't know it at the time, but it was "condensation induced waterhammer". It was a 3" 125# cast iron gate valve, and knowing what I know now, I don't know why the bonnet didn't blow out off that valve. It made a BIG impression on me, and the guy down the hole too. Chubby Scott made possibly the greatest standing vertical leap in the history of man. I don't think he touched even one rung on that ladder, as he exited the hole at high velocity. At the end of it, we didn't even have a leak at a gasket or the packing gland. Nobody was hurt, and no damage was done, but it scared us - a LOT. When I stumbled across Wayne Kirsner's article "What Caused The Steam Accident That Killed Jack Smith?" a couple of years later, I thought as I read it "Hey - I recognize this waterhammer...".
  • jeff_51
    jeff_51 Member Posts: 545
    4\" steam main

    at blackstome coporation in Jamestown N.Y. Steam system was shut down for maint over the summer. Evidently had a low spot in the main. When they turned the system back on, the trapped water held back the steam untill......Then blew off a 4" welded 90 on the end of the run. Nobody hurt, but ZOWIE.
  • tls_9
    tls_9 Member Posts: 89
    makes you stop and think....

    how many places concider that banging as just a normal part of a steam system. If they only knew.

    Remember that system we looked at that was blowing all them coils, they never did take any of our recomendations.

    tom
  • Dale
    Dale Member Posts: 1,317
    Blowing steam

    My company is putting a new co gen plant on line soon. This week we were blowing steam lines to the air, downtown university site so quite a few complaints. Part of the reason of course is safety, clean and warm up the lines so you don't generate a huge condensate load on startup. The pictures shown here are why that's not a good idea.
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443
    Hey Tom

    Haven't seen you here for a while - good to have you back.

    About the steam system we looked at - doesn't really surprise me that they never did anything. I'll bet at least half of the situations like that that I look at, just get left as they are. And it almost always costs them more to leave it, than fix it. "You can lead a horse to water..."
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443
    It's Not Always...

    ... at start-up. Kirsner's report on the 18" 200 PSIG steam line that blew-out in Scotland indicates that nobody had touched a valve for several hours, and that the line was basically just sitting there - quietly filling with condensate - until...

    The photographs of blow-outs also show a couple of instances of valves installed in vertical steam lines. I've never liked to see valves in lines like that, unless there's an over-seat drain. Even if the steam flow is coming up the vertical, if the valve leaks-by a little, you can still wind up with a slug of condensate sitting on top of a closed valve.
  • tls_9
    tls_9 Member Posts: 89
    So...

    How you been Tony? Lots of work north of the border? I hear theres a couple of more of them heat exchangers down this way. You selling lots of them? Hope I can sneak in there and get a look at them someday.

    tom
  • Tony Conner_2
    Tony Conner_2 Member Posts: 443
    The Heat...

    ... exchangers and piping combination do OK. They kind of even things out. If there's not much piping work going on, there are usually some HX sales happening, and vice versa.

    It worked out well that we could pull those two big HX's out of stock. Can't always do that for a building heating loop with a 350 GPM water flow :) Your brother John designed the piping layout, and Giltinan (spelling?) did a nice job on the installation.
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