HDPE-Stainless fittings

[RAKM]

Hi guys,

Good day! I have a few problem in my piping, I try so many ways to address the leak of the threaded connection of HDPE pipe but still the problem keep coming back. For the reference the connection is HDPE-SS fitting which is use for pressure monitoring and sampling point. I was thinking to use PVC adapter as my connector in between.

Thanks a lot

 

[moltenmetal]

It's hard to understand what you are asking and what your problem is.

Does your HDPE fitting have a female NPT port, which you are threading a stainless steel male NPT fitting into? If the connection is small (1/4" NPT) and that kind of joint is leaking, you need a better thread sealant rather than a different type of fitting. For plastic to metal joints, you need a flexible anaerobic pipethread sealant which is compatible with the plastic you're using. Tape type sealants are insufficiently flexible to handle the creep and thermal expansion/contraction which is inevitable in an HDPE to metal joint of this type.

If the thread is a male NPT on the end of a piece of HDPE pipe, you need to weld a lapjoint flange on there instead, and put your instrument connection on a blind flange.