US Patent 7802590 Switch valve having leakproof function

A switch valve includes a valve seat, a valve body, a ceramic plate unit, a control shaft, and a control handle. Thus, the ceramic plate unit is rotatable in the valve body to open or close the water flow so that the valve body will not rub the valve seat constantly to prevent the valve body and the valve seat from being worn out due to the friction, thereby enhancing the lifetime of the switch valve. In addition, the ceramic plate unit has a wear resisting function to prevent a gap from being formed between the ceramic plate unit and the valve body during a long-term utilization, so that the ceramic plate unit has a leakproof function, thereby enhancing the working efficiency of the switch valve.