I would like some advice regarding the pressure rating of gaskets used for entering and exiting heat exchangers!
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Generally, the gasket pressure rating for pipes entering and leaving the heat exchanger should be increased by one grade. What is the reason for this? What’s the problem if you don’t get promoted to the next level?
I usually choose a higher grade for the inlet and outlet flanges of heat exchangers; I haven’t heard that the pressure grade of gaskets needs to be increased as well. Higher-grade flanges are chosen for import and export applications due to temperature considerations; at higher temperatures, the maximum allowable operating pressure of the flanges must be reduced. The specific value depends on the pressure-temperature relationship table specified in the flange standards. In addition, the stresses exerted on the pipeline during actual operation are also taken into consideration. The result of comprehensive consideration.
That’s exactly what I meant by asking. However, based on practice, it seems that temperature doesn’t play a very big role in this regard. If the flange is of a higher grade, then the gasket naturally needs to be of a higher grade as well. But what problems could arise if the gasket isn’t of a higher grade, even though its strength is much higher than the working pressure?