Heat exchanger tubesheets are not flanges at the same time. How to ensure the parallelism of the two tubesheets?

Heat exchanger tubesheet is not used as flange at the same time. How to ensure the parallelism of the two tubesheets?
2019-05-05 Reply
What does it promise to do? It's about so good.
2019-05-05 08:48:49 Reply