Air admittance valve preventing mephitis overflow

摘要

An air admittance valve preventing mephitis overflow, having a main body with an air entry guide base defining an air entry guide; a pivot support; and a valve seat. A sealing valve group having a sealing valve body that defines a recess; a flexible member; a pivot housing; and a pivot. The valve seat is located about the air entry guide. The pivot is located in the pivot housing and the pivot support, and the pivot is located along, or adjacent to, the center of gravity of the sealing valve body. The flexible member is at least partially located in the recess and abuts the main body; and when the air admittance valve is closed, the sealing valve body abuts the valve seat.