Patent ID: 8727313

Claim:
A tri-eccentric valve with a symmetric drain-proof ring, comprising: a valve body ( 1 ) having a chamber ( 10 ) therein; a wall of the chamber being formed with an annular trench for receiving an annular seat ( 30 ); a radial cross section of the annular seat having a trapezoidal shape; the annular seat ( 30 ) being detachable; a stem ( 2 ) penetrating through the valve body ( 1 ) so as to protrude into the chamber ( 10 ); a top end protruding from the valve body ( 1 ) having an operation unit for driving the stem ( 2 ) to rotate; a valve disk ( 31 ) installed in the chamber ( 10 ) of the valve body ( 1 ) and contacting an inner wall of the annular seat ( 30 ); a radial hole ( 310 ) being formed radially along the valve disk ( 31 ) for receiving the stem ( 2 ) so that rotation of the stem will rotate the valve disk for opening or closing the valve; and a rear side of the valve disk ( 31 ) being formed with a stepped recess ( 311 ); the valve disk ( 31 ) being formed as an asymmetric conical shape; a waterproof washer ( 33 ) being a ring and being received in the annular trench of the valve disk ( 1 ); and a drain-proof ring ( 32 ) being an O ring and being arranged in the stepped recess ( 311 ) of the valve disk ( 31 ) to seal the waterproof washer ( 33 ); the drain-proof ring ( 32 ) being symmetric to the axis of the ring; in assembly state, a periphery of the drain-proof ring ( 32 ) resisting against an inner wall of the annular seat ( 30 ) so as to tightly seal the space between the drain-proof ring and the annular seat; and wherein after assembly, a left side of an outer periphery of an assembled structure including the valve disk ( 31 ), the waterproof washer ( 33 ) and the drain-proof ring ( 32 ) has a conical shape; and when the waterproof washer deforms, the drain-proof ring has flexibility, which can compensate for the gap due to the deformation.