Pressure for pneumatic testing of the jacket of low-temperature storage tanks

1. How did the original poster determine the test pressure? The pneumatic test pressure for the inner cylinder should be 0.92, and a test pressure of 0.11 for the jacket is acceptable. 2. For two-chamber pressure vessels, it is necessary to first verify the stability of the inner cylinder during the pressure test carried out on the jacket. If the stability requirements are not met, a leak check should be conducted first; only after it is successful can the pressure test be performed. The inner cylinder must be maintained at a certain pressure such that the pressure difference between the inside and outside does not exceed the allowable value.

Using 150 as the value, the pressure for the pneumatic test of a container subjected to external pressure is 1.1 times the design pressure; that is, 1.1*0.1 equals 0.11. Thus, a pneumatic test of 0.11 MPa is carried out on the jacket, and in this case the inner container is subjected to an external pressure of 0.11 MPa. It is necessary to first use SW6 to calculate parameters such as the wall thickness, reinforcement rings, and calculation length required when the test pressure on the inner container is -0.11 MPa If these parameters can meet the requirement of an external pressure of 0.11, it is not necessary to apply pressure to the inner container during the jacket pressure testing; if they cannot meet this requirement, the inner container must first be pressurized, ensuring that the external pressure it experiences does not exceed the maximum allowable value calculated Is that so?

If the stability requirements cannot be met, a leakage test shall be conducted in accordance with GB150 first; only after it passes can a pressure test on the jacket be carried out using the pressure difference method. The starting point of the standard is that if there is a leak between the inner cylinder and the jacket at this time, it will be impossible to determine where the leak is located.

It’s a bit messy; it should be done according to the calculation requirements. Is it necessary to maintain pressure in the inner cylinder? Of course, the inner cylinder should be made first; after the jacket welding is completed, then the jacket is fabricated, followed by hydrostatic testing and pressure testing.

This post was last edited by wanlirn on 2018-1-31 at 18:12. The original poster, your concepts of various pressures such as calculated pressure, design pressure, test pressure, etc., within the value of 150 are confusing. Take a close look at 150 – the consideration of internal and external pressure differences is part of the calculated pressure. In your example, the design pressure for the inner cylinder is 0.84, and the pneumatic test pressure is 0.84*1.1; the design pressure for the outer cylinder is -0.1, and its pneumatic test pressure is 0.1*1.1. The inner cylinder needs to be pressurized first, to a level of 0.84*1.1. The jacket should be pressurized first as well. How will you check whether there are leaks when testing the pressure of the inner cylinder?

Professional design of cryogenic liquid storage tanks addresses the following: the design pressure for the inner tank is 0.84 (gauge pressure), while the design pressure for the outer tank is -0.1. The inner tank is not subjected to any pressure within the outer tank; therefore, the pressure test pressure is 1.1×0.94. Generally, the outer tank is not tested under pressure. As long as the vacuum is maintained and there are no issues with helium leak testing, it’s fine. If the jacket is pressurized. The pressure inside the inner cylinder is not less than the pressure in the jacket.

Professional design of cryogenic liquid storage tanks addresses the following: the design pressure for the inner tank is 0.84 (gauge pressure), while the design pressure for the outer tank is -0.1. The inner tank is not subjected to any pressure within the outer tank; therefore, the pressure test pressure is 1.1×0.94. Generally, the outer tank is not tested under pressure. As long as the vacuum is maintained and there are no issues with helium leak testing, it’s fine. If the jacket is pressurized. The pressure inside the inner cylinder is not less than the pressure in the jacket. Can this jacket be exempted from pressure testing?

Can this jacket not be designed in accordance with GB150? It shouldn’t be considered a container

The jacket has not been subjected to pressure testing for ten years; helium leak testing has been used instead.