▎ 摘　　要

NOVELTY - The device comprises a vacuum chamber provided with an upper observation port, a lower observation port and a clamping device. The upper and lower observation ports are welded with the chamber through upper and lower flanges. A top part of the chamber is provided with an upper cavity sealing flange provided with an annular groove. The annular groove is connected with an inner side of the upper observation port flange through a bolt. The upper observation port flange is provided with a sealing ring. An upper part of the chamber is provided with a top flange. USE - The device is useful for preparing graphene (claimed). ADVANTAGE - The device has the facility to visualize the growth process during the graphene preparation. DETAILED DESCRIPTION - The device comprises a vacuum chamber provided with an upper observation port, a lower observation port and a clamping device. The upper and lower observation ports are welded with the chamber through upper and lower flanges. A top part of the chamber is provided with an upper cavity sealing flange provided with an annular groove. The annular groove is connected with an inner side of the upper observation port flange through a bolt. The upper observation port flange is provided with a sealing ring. An upper part of the chamber is provided with a top flange that is connected with the upper cavity sealing flange by the bolt. The clamping device is provided with a holder, a threaded post, and the bolt and a screw. One end of the holder is fixed on the lower flanges to the threaded post by the screw. Another end of the holder is connected with lower observation port sealing flange. A side wall of the chamber is provided with a gas inlet door and a gas outlet door. The lower observation port flange is welded with a lower cavity sealing flange through a lower observation port sealing ring. A lower part of the chamber is provided with a bottom flange that is connected with the lower cavity sealing flange by welding through the bolt. The upper and lower observation ports are made of transparent materials.