Problems of pressure vessels under instantaneous loading
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Our company has several storage tanks, with a normal operating pressure of ATM. When the tanks are full, N2 gas at a pressure of around 6 KG/CM2 is used to transfer the contents to other tanks; this process takes approximately 1–5 minutes, and the cycle time ranges from 0.5 to 3 months. I would like to ask whether such containers can be considered pressure vessels. Thank you! :)
It should be considered a pressure vessel; the regulatory standards specify the working pressure, but not the duration of use – even short-term use means the equipment cannot withstand it
Article 3 of the regulatory standards specifies how long exactly the instantaneous pressure during the discharge process lasts. . . . :L
According to the pressure vessel regulations, instantaneous pressures greater than or equal to 0.1 MPa are no longer within the scope of these regulations. I think 3-5 minutes isn’t an instant, so it should be a low-pressure container.
We also encounter this problem frequently, especially when it comes to equipment purchased from abroad; since the manufacturers do not have a pressure vessel manufacturing license in China, it becomes very troublesome to handle such situations. It’s a simple matter; it’s not possible to force manufacturers to obtain the necessary certifications right now, as there’s no time for that. Moreover, such equipment usually comes with patents, and even if there are no patents, it’s better to buy it from authorized manufacturers to ensure safety. However, manufacturers generally feel that the regulations aren’t clear enough, and since they have been producing this type of equipment for many years, they think that if customers want to buy it, they can do so, and if not, it’s not their problem.
I think it should be a pressure vessel.
It must be a pressure vessel. The time is around 1–5 minutes, which is not considered instantaneous; the loading rate of the pressure vessel is less than 1 kilogram per second
The stress during the material pressing process does not fall under pressure vessels.
It should fall outside the scope of application of the Pressure Vessel Regulations. According to Article 3, Paragraph 5 of these regulations, vessels that must withstand a pressure of 0.1 MPa or more momentarily during material loading and unloading are not covered by the Pressure Vessel Regulations. Although the pressure of the gas source in this case is 0.6 MPa, since only the frictional losses along the pipeline need to be overcome when the gas is delivered to other tanks, the actual pressure exerted on the tanks is quite low; therefore, this situation should not fall under the scope of the Pressure Vessels Regulations.
It indeed falls outside the scope of application of the Code of Practice. For safety, register with the local quality and technical supervision department and ask them to conduct inspections.