How should devices that may experience positive pressure or negative pressure during operation be designed and calculated?
Thread Content
How should containers that may experience positive or negative pressure during operation be designed and calculated? Should positive and negative pressures be designed, calculated, and verified separately? Or, since there are no issues even with a positive pressure of 5 MPa, then surely there will be no problems either with a negative pressure of -80 KPa; therefore, is it not necessary to conduct any checks for negative pressure? Generally, when negative pressure is involved, a design pressure of -0.1 MPa should suffice, right? Because this is the limit of negative pressure (that is, absolute vacuum)
Various operating conditions should be calculated separately in order to have a complete design document
Design criteria are established separately for positive and negative pressures, and the design is verified in accordance with each set of criteria
Calculations are performed for different operating conditions separately. 2. As for the negative pressure value, it’s generally correct. However, in the case of jackets, heat exchangers, and other multi-chamber containers, be cautious as there might be a higher negative pressure value.
-0.1/5.0MPa
The theories for calculating positive and negative pressures are different; therefore, calculations must be performed separately for positive and negative pressure conditions, and the one with the greater required thickness should be chosen.
So you need to know the frequency of variation to see if it meets the conditions of fatigue under alternating loads, and to determine the design standards. If it is a conventional design, then all of these factors must be taken into account; internal pressure and external pressure cannot be reliably compared with each other.
I don’t know much about design, but the fact that a device can withstand positive pressure doesn’t mean it can handle negative pressure as well. Even a very small amount of negative pressure can cause the device to be crushed; it’s completely different
It still needs to be verified at -0.1 MPa.