The invention belongs to the technical field of
chemistry, and provides a
steel cylinder special for electronic grade chemicals, which comprises a cylinder body and a protective cover, the protective cover is detachably connected with one end of the cylinder body where a valve is located, and a partition plate is fixedly mounted in the protective cover. The technical problem that in the prior art, a protective cover cannot solve the problem that pressure is increased when gas continuously leaks is solved. A first
piston plate is pushed by air pressure to move downwards, an air inlet
pipe is closed through a first permanent
magnet and a third permanent
magnet which are matched when the first
piston plate moves downwards, at the moment, the first
piston plate is pushed to move upwards when the air pressure in a protection cover is increased, and therefore pure
nitrogen in an air cylinder is discharged into
external storage equipment; and meanwhile, after the first piston plate moves to the upper end, the gas inlet
pipe is opened again through a first permanent
magnet and a third permanent magnet which are matched with each other, and pure
nitrogen continuously leaked from the
bottle body can be conveyed into
external storage equipment by repeating the steps. The sealing device is widely applied to the operation scene that gas is exhausted from the sealing cavity.