The gas storage tank is one of the necessary common equipment in the user's workshop. It can store compressed air, nitrogen, oxygen, carbon dioxide and other gases. It can be used to drive subsequent equipment, or it can only be used for storage. The gas storage tank is a special equipment and is a national key monitoring equipment. Its design, production, manufacture and use must strictly comply with the relevant national regulations. Generally speaking, the gas storage tank is a closed container, and its airtightness causes great inconvenience to subsequent inspections. Therefore, in the design process, inspection holes are generally provided for the convenience of inspection and maintenance (especially small pressure vessels can also be No inspection hole), the size of the inspection hole is determined according to the volume of the gas storage tank, and it must also meet the relevant regulations.