Pull out test or Heat Exchangers

[Merzi]

We are planning to perform Pull out test on Tube to tube sheet mock up.

customer specs does not specify the number to tubes and at what location to be tested. Can any one help me.

Regards

Merzi

 

[EdStainless]

Write your own procedure. Often I have seen people mock up a section of tube sheet that will hold 16 or 24 tubes. They roll 3-5 each at 3-5 different torque levels. Depends on how much variation you expect.
Is this new construction? If so it is easy to match materials.
If it is a retube then you must be careful to match the properties of the tubes sheet. Then you have to roll in 'original' tubes, and pull them out. Then roll in your re-tube and test.

Of course you actuall are testing push-out strength. The test setup is so much easier.

= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[metengr]

The pull out test is used with a mock-up to qualify your tube rolling procedure. You need to first generate a tube rolling procedure for this job and determine the optimum toque setting for rolling the tubes based on a desired tube wall reduction. You cannot use just pull out strengths because this can be misleading.

What you are attempting to do is to assure a minimum tube wall reduction is met to avoid failure of the tube or leakage of the roll joint in service. Depending on your application, I have seen typical tube wall reductions of 8-12% for stainless and carbon steel tubing.

 

[ijzer]

A mock up can also be required for welded connections. You could use the method per ASME VIII-1 appendix A . It requires at least 9 tubes to be tested.