Vacuum extraction device for non-convex extraction nozzle

The vacuum extraction device comprises a cover body, a through hole is formed in the center of the cover body, a pull rod in sliding fit with the through hole is arranged at the position of the through hole, a rod head matched with a groove in the top of a vacuum end socket is arranged at the bottom end of the pull rod, and a step is inwards arranged in the middle of the pull rod. A plurality of annular sealing grooves are formed in the pull rod between the step and the rod head in the length direction of the pull rod, sealing rings are installed in the sealing grooves, and a cushion block is further arranged between the step and the outer wall of the top of the cover body. The vacuumizing device is suitable for the non-protruding vacuumizing nozzle type low-temperature storage tank, the vacuum end socket can be conveniently opened during vacuumizing and closed after vacuumizing is completed, vacuumizing operation is simple and rapid, opening or closing of the vacuum end socket is completed in a sealed enviro