Anti-coking gate valve

The invention relates to an anti-coking gate valve which comprises a valve body, a valve seat, a valve deck, a gate plate, a valve rod and a driving device. The valve seat is arranged in the valve body. The valve rod and the gate plate are movably connected through a movable sleeve. The upper end of the valve body is fixedly connected with the valve deck. The upper end of the valve rod is fixedly connected with the driving device. A sealing belt is arranged at the position, making contact with the gate plate, of the valve seat. The lower end of the gate plate is provided with a through groove. The upper end of the through groove is provided with at least one small hole. The small hole is communicated with the through groove. The small hole is higher than the sealing belt at the lower end of the valve seat when the gate plate is closed. The bottom end of the gate plate is provided with the through groove, so that smooth flowing of media is guaranteed. The through groove is provided with the small hole, and the height of the small hole should meet the condition that the top end of the small hole is located above the sealing belt of the valve seat when the valve is closed so that the media can slowly flow in a pipeline regarding the abrasion stroke of the gate plate, heat can be transmitted, coking cannot happen, and heat supply is not needed for preventing the media from coking; in this way, consumption of energy can be reduced.