4 replies to this topic

[pleckner]

The blocked-in senario you refer to usually is discussed in terms of tube-side protection. If we were to assume your question refers to the tube-side, then no, the tubes will be able to handle a vacuum condition. And besides, and I've been beating this one to death, there is no code that requires the exchanger tubes to be protected from failure, just the shell (assuming this is to be designed as a pressure vessel in the first place).

Just for information, the shell-side of a heat exchanger should be protected against vacuum and one way is with a vacuum breaker. However, if a vacuum could develop in the shell, I would just design the shell for full vacuum and be done with it.

[pleckner]

In a liquid filled system, we are concerned about thermal expansion because just a tiny amount of expansion will cause a huge pressure increase. If the dynamics went the other way, I seriously doubt you would experience any realistically detectible drop in pressure due to liquid contraction; it just wouldn't matter. Remember, even an atmospheric API vessel will take an inch of water pressure or so and a few ounces of vacuum. These components you are talking about had better be designed better than this.

So, without seeing any numbers to the contrary, that's my take; which maybe why I haven't really seen this as a problem in the past.