Hot Oil Piping, method or sealant.
Hot Oil Piping, method or sealant.
(OP)
Got a problem with a two roll lab mill using Paratherm NF, like a mineral oil, at a temperature of 380F. Piping is 1"npt carbon steel. We can't stop the leaks at the threads. We reworked all the piping using the factory recommended Permatex High Temp Pipe Dope, but it didn't work. What is the best method for piping, ie should I be using flared tubing or compression fittings, and what is the best pipe sealant for convential NPT steel pipe. Also, and idea how to seal a pipe union, or should I just replace with flanges.





RE: Hot Oil Piping, method or sealant.
I've never used Permatex - is there a cure-time? If all else fails, have you considered X-Pando? It's typically got a 24 hour cure-time which doesn't usually lend itself to maintenance work. Production people always want the line back in service about 15 minutes ago, and aren't interested in cure-times.
RE: Hot Oil Piping, method or sealant.
RE: Hot Oil Piping, method or sealant.
not much help, but . . .
good luck!
-pmover
RE: Hot Oil Piping, method or sealant.
Welding works well.
RE: Hot Oil Piping, method or sealant.
Get rid of threaded unions and replace with pairs of flanges. If there isn't enough room for flanges, replace with a union which has a brass seating ring. Ordinary steel to steel or MI to MI unions are notoriously leakage-prone.
Threaded piping gets a bad name because people don't know how to do it properly, use it in inappropriate services, and use incorrect sealants. Properly done, threading is a very efficient and flexible method of joining pipe below 2" NPS, and can be used for far more than air and water.
RE: Hot Oil Piping, method or sealant.