| CPC A47J 47/02 (2013.01) | 5 Claims |

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1. A box lid, comprising:
a lid body (100); and
a sealing ring (200) connected to the lid body (100), the sealing ring (200) comprising an inclined portion (210) inclined inwards, wherein the inclined portion (210) can produce elastic deformation and is deformable to a sealing state;
when the inclined portion (210) is in the sealing state, one end of the inclined portion (210) is in contact with the lid body (100), and the other end is away from the lid body (100); a gap (110) is formed between a portion of the lid body (100) close to and located directly above the inclined portion (210) and the inclined portion (210); the gap (110) is shaped as an acute angle; angle of the gap (110) is constant, and size of the gap gradually decreases from the center of the lid body to its edge; and a lower surface of the inclined portion (210) is at an angle that can fit a surface (310) to be sealed;
when the gap (110) is in a positive pressure environment, the inclined portion (210) is pressed by a pressure toward the surface to be fitted;
the inclined portion (210) has an annular tapered structure, a tail end of the inclined portion (210) is an annular resistance end (211), and an inner edge surface of the annular resistance end (211) has an arc structure;
the cross section of the inclined portion (210) is tapered;
the lid body (100) is provided with two fastening lugs (130), and the two fastening lugs (130) are respectively located on two sides of the lid body (100).
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