What are the design differences between negative-pressure containers and positive-pressure containers?
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Hello everyone! Our factory has a tank with a diameter of 2400 mm and a total height of 8750 mm; its operating pressure ranges from 0 to 6.56 MPa. Negative pressure may occur inside the tank during operation. I would like to know what are the design differences between tanks designed for positive pressure and those designed for negative pressure, as well as to assess how high the risk of negative pressure formation is. Thank you!
Do you mean vacuum by negative pressure? If it is a vacuum environment, design it first for a positive pressure of 6.56 MPa, and then conduct a vacuum verification. As long as the equipment thickness meets the requirements for internal and external pressures, there is no risk; it is important to note whether the equipment is a fatigue-sensitive vessel
For negative pressure, the stiffness issue must be taken into account, that is, the issue of instability； Positive pressure takes strength into account. . .
Negative pressure is taken into account during design, and the cylinder is checked for external pressure.
For low-pressure equipment, a negative pressure is applied and an external pressure reinforcement ring is added to the cylinder in order to save material. For the equipment mentioned by the original poster, since the positive pressure is high, it seems unnecessary to add such a ring. If you’re not sure, you can use SW6 to calculate it.