It is hard to get a good tight rolled (or expanded end) "pipe" to fit in the tubesheet - "pipe" has much wider tolerance bands for OD and ID than "tube". Surface roughness is also different.
No it is not existing. We planning to build a new heat exchanger. Just our client want to cut cost as pipe is cheaper than tubes. I know that the code is silent about this,but by experience somebody could tell any drawbacks of using pipe instead of tubes.
abangbikerz, like others have said you will be pretty much be stuck with welded tube-tubesheet joints.
It seems to me that for a given service the HX will be physically larger as well, as you may need more pipes (smaller ID for a given OD)) than you would tubes and I doubt you can array them as closely as you can pipestubes. This, of course, is guesswork on my part.
But from a Code standpoint, it is permitted. It is common in waste heat boilers for one example.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
Given the very large tolerance on pipe (both OD and wall) You will end up with a poorer performing HX.
What is wrong with tube?
And I should add that many times pipe is not either Eddy Current tested or leak tested, not a good plan for a HX.
I don't think like is cheaper than tube. You need to whom around and save. Rolling erw pipe is almost impossible, using g seamless it's expensive. So the is the answer. I use both so it all depends on the design and tooling available. Rolling pipe will require special tools as well. Ed: Code pipe is NDT and pressure tested it's a requirement.
We managed to get a price quotation for seamless pipe that is cheaper than tubes. Edstainless have a good point. Pipe making process is less precise than tubes. And it is not leak tested.
Can you give us more details like size/wall thickness of tubes and pipes, tubes ASME spec? Also process data like type of fluid temperatures and pressures wouldn't hurt. It is because people need to see everything in prospective in order to give you correct answer.
By the way, are tubes and pipes are quoted by weight? What is price difference we are talking about?
GenB, 1,000psi hydro is neither a good NDT nor a very sensitive leak test.
The tube specs in general require 100% ET and then either air-under-water or hydro.
We actually have customers that order tube to a pipe size for HX work. The original was designed for pipe but they want tighter tol and more NDT.
The use of SA 312 pipe material is subject to either a hydrostatic test or NDT per SA 999. The hydrostatic test must provide a stress that is 50% of the SMYS for stainless steel pipe. It all depends on the purchase order and end use regarding minimum requirements.
