Plant Operations/Maintenance/Freezing HDPE

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Question
Hi Fred,
have you frozen large diameter HDPE (24")? If so, how long did it take and roughly how much LN2 did you use? Do you have issues with the pipe contracting and breaking the seal around the freexe jacket when freezing these materials?
Thanks

Answer
Hi Matt,
It takes 4 large bottles of nitrogen per hour ( 44 GAL bottles ) to keep the clamp full of nitrogen. Give or take it takes about 16 hour's to get a good plug.
Plus the number of hours you need for repair time. You will need two ports at the bottom of the clamp to pump nitrogen through. Set up 2 tanks with a splitter on each side. This will allow you to change bottles without interupting the nitrogen flow to the clamp.


Theres always a chance it will leak around the seal, Do a good job cleaning the clamp closing area's. I just keep a water spray bottle handy to spray into any leaking area to make a quick ice plug.

Any more questions just ask.
         Fred

Plant Operations/Maintenance

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Fred Thibodeau

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Controlled pipe freezing: I can answer questions about how pipe freezing with liquid nitrogen can help you isolate a section of pipe for repairs under full system pressure without the need to shut down or have to drain the system. Water, oil, chemicals can be frozen safely to allow your maint. department to do the needed repairs.Freezing can be done on steel, copper, cast, PVC pipe, etc. I have frozen pipes at 1500 lbs pressure and up to 24" in Dia.

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NSTAR,Com energy,Sithe Energy,Boston Edison,Electric Boat, Mead Paper,etc. Many mech. contracting companys

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