Water stop structure of drain valve

A water stop structure of a drain valve comprising:

• a body made of metal, and the body including a chamber defined in the body, wherein the chamber has an obliquely conical abutting face formed on an upper portion of an inner wall thereof, and a diameter of the obliquely conical abutting face is gradually reduced from a top of the obliquely conical abutting face to a bottom of the obliquely conical abutting face, wherein the obliquely conical abutting face has at least two arcuate recesses defined thereon, and a diameter of a respective one arcuate recess of the at least two arcuate recesses is reduced from a top of the respective one arcuate recess to a bottom of the respective one arcuate recess, the body further includes a first receiving orifice defined on a top thereof and communicating with the chamber, and the first receiving orifice has a first threaded section formed on an inner wall thereof, the body includes a coupling orifice defined on a other side thereof and communicating with the chamber, and a second receiving orifice defined on a bottom of the body and communicating with the chamber;
• a ball valve rotatably received in the chamber, and the ball valve including a first discharge orifice, a second discharge orifice, and a stop face which are defined around the ball valve in turn, wherein the first discharge orifice and the second discharge orifice communicate with each other;
• a second support ring made of non-metallic material and being circular, and the second support ring including an arcuate face defined on an inner wall thereof, a top of the chamber and above the ball valve, a resilient element accommodated in a top of the second support ring, wherein the second support ring further includes an obliquely conical abutting face formed on an outer wall thereof, and a diameter of the obliquely conical abutting face is reduced from a top of the obliquely conical abutting face to a bottom of the obliquely conical abutting face, the obliquely conical abutting face has at least two arcuate protrusions corresponding to the at least two arcuate recesses, wherein a diameter of a respective one arcuate protrusion of the at least one arcuate protrusions is reduced from a top of the respective one arcuate protrusion to a bottom of the respective one arcuate protrusion, and a radian of the respective one arcuate protrusion is smaller than a radian of the respective one arcuate recess, such that the at least two arcuate protrusions and the at least two arcuate recesses contact with one another to stop water closely, and a movably annular stop line is defined between the respective one arcuate protrusion and the respective one arcuate recess so that when the second support ring is driven by the ball valve to move upward and downward, the at least two arcuate protrusions and the at least two arcuate recesses changeably contact with one another at different positions to produce a height change, to maintain a water stopping effect and a damping of a rotation of the ball valve;
• a positioning ring including a through orifice defined on a center of the positioning ring and formed in a circle shape, a second threaded section formed on an outer wall of the positioning ring and configured to screw with the first threaded section, a bottom of the positioning ring is biased against the resilient element so that the resilient element forces the second support ring and the positioning ring;
• and
• a connection portion connected with the ball valve and configured to control the ball valve to rotate.