Conventionally, for a sink and its sewer port of a family kitchen, a urinal of a toilet, a floor drain and its sewer port, waste water may overflow in case of a slight clogging. Sometimes a floating bell-shaped cover of the floor drain is removed to prevent clogging, although this can address the issue of sewage clogging, a strong bad smell is emitted from the sewer, thus polluting the environment and affecting people's health.
Reference is made to FIG. 1, which is a schematic view showing the structure of a deodorant anti-overflow backwater valve. The working principle and the technical defects of the backwater valve are briefly described hereinafter.
As shown in FIG. 1, the backwater valve has a floater 1′ connected to one end of a lever 2′, another end of the lever 2′ is a fulcrum 3′, a middle portion of the lever 2′ passes through a through hole at a top end of a connecting rod 7′, and a bottom end of the connecting rod 7′ is connected to an interlocked bell-shaped cover 8′, and an edge of the interlocked bell-shaped cover 8′ is arranged in an annular concave water seal 9′.
With this structure, when the waste water from an upper sink is discharged into a lower sink, the floater 1′ will float according to the amount of the waste water in the lower sink, and bring the connecting rod 7′ to move by the lever 2′, to drive the interlocked bell-shaped cover 8′ below the connecting rod 7′ to move up and down to be opened and closed. When a large amount of waste water is stored in the lower sink, and the floater 1′ floats high and drives the lever 2′ and the connecting rod 7′ to move upward, and the interlocked bell-shaped cover 8′ is widely opened. When the waste water is drained, the floater 1′ will fall down to press the connecting rod 7′ downward by the lever 2′, and thus the interlocked bell-shaped cover 8′ is tightly covered in the annular concave water seal 9′ at a lower part of the floor drain, which blocks out the bad smell.
However, when the waste water in the lower sink is drained rapidly, the air pressure in the drainpipe will drop, thereby generating a negative pressure, and generating a suction effect on the interlocked bell-shaped cover 8′, and tightly suctioning the interlocked bell-shaped cover 8′ to the bottommost end of the annular concave water seal 9′. In addition, the suction force is great, and when waste water in the upper sink is discharged again into the lower sink, a greater buoyancy force is required to pull the interlocked bell-shaped cover 8′ upwards, thus bringing inconveniences to water drainage.
In view of this, it is urgent to make a further optimized design to the multi-layer water sealing device in the conventional technology to address the above technical problems, to prevent the bell-shaped cover from being suctioned onto the bottom end of the water sealing box while ensuring a large flow drainage, and improve the working stability of the water sealing device.