More than three months. In the training of Shanxi Mobile Pressure Vessel Operation Certificate, those who are over 18 years old, are in good health and have no diseases or physical defects that hinder pressure vessels must go through three months of internship operation and then participate in theoretical training for more than three months. Mobile pressure vessel refers to the pressure vessel which is used for filling gas and can be transported. This kind of ship has no fixed use place and operators, and its use environment often changes, and it has to bear other additional loads during handling.