Drain structure

Abstract

A drain structure used for mounting in a pipe includes a ring wall, a bottom plate and a chamber, wherein at least one overflow hole mounted on the ring wall communicates with an inner ring wall and an outer ring wall. The overflow hole comprises a first opening and a second opening, wherein the first opening comprises a top edge, and the second opening comprises a bottom edge. A first horizontal surface passes through the top edge of the first opening, and a second horizontal surface passes through the bottom edge of the second opening, wherein the first horizontal surface is not higher than the second horizontal surface to form a first water tank between the second horizontal surface and the bottom plate. Liquid accumulated in the first water tank is able to prevent insects and gases in outdoors from entering indoors via the pipe.

What is claimed is: 
     
         1 . A drain structure including a ring wall, a bottom plate coupled with the ring wall and a chamber located above the bottom plate, the ring wall surrounds the chamber and comprises an inner ring wall and an outer ring wall, the chamber comprises an opening for liquid flow into the chamber, wherein at least one overflow hole mounted on the ring wall communicates with the inner ring wall and the outer ring wall, a liquid flow passage is formed by the opening, the chamber and the overflow hole, wherein the overflow hole comprises a first opening located on the inner ring wall and a second opening located on the outer ring wall, the first opening communicates with the chamber and comprises a top edge, the second opening comprises a bottom edge, wherein a first horizontal surface passes through the top edge of the first opening, and a second horizontal surface passes through the bottom edge of the second opening, and the first horizontal surface is not higher than the second horizontal surface to form a first water tank between the second horizontal surface and the bottom plate. 
     
     
         2 . The drain structure in accordance with  claim 1  further includes an external ring wall coupled with the ring wall, wherein a second water tank is formed between the external ring wall and the ring wall, the external ring wall comprises an exposing terminal, an overflow opening is formed between the exposing terminal and the ring wall, wherein a third horizontal surface passed through the exposing terminal is not lower than the second horizontal surface. 
     
     
         3 . The drain structure in accordance with  claim 1 , wherein the top edge of the first opening is located in the first water tank. 
     
     
         4 . The drain structure in accordance with  claim 2 , wherein the top edge of the first opening is located in the first water tank. 
     
     
         5 . The drain structure in accordance with  claim 1 , wherein the ring wall is a conical ring wall. 
     
     
         6 . The drain structure in accordance with  claim 2 , wherein the ring wall is a conical ring wall. 
     
     
         7 . The drain structure in accordance with  claim 1 , wherein an included angle is defined between a vertical line passed through the first horizontal surface and a center line passed through the overflow hole, and the included angle is an acute angle. 
     
     
         8 . The drain structure in accordance with  claim 2 , wherein an included angle is defined between a vertical line passed through the first horizontal surface and a center line passed through the overflow hole, and the included angle is an acute angle. 
     
     
         9 . The drain structure in accordance with  claim 1  further includes a supporting ring, wherein the supporting ring is coupled with the outer ring wall of the ring wall. 
     
     
         10 . The drain structure in accordance with  claim 2  further includes a supporting ring, wherein the supporting ring is coupled with the outer ring wall of the ring wall. 
     
     
         11 . The drain structure in accordance with  claim 1 , wherein the ring wall is formed as one piece with the bottom plate. 
     
     
         12 . The drain structure in accordance with  claim 2 , wherein the ring wall is formed as one piece with the external ring wall.