Downhole portable small-sized automatic drainage device

The utility model relates to an underground portable small automatic drainage device, which belongs to the field of coal mine drainage equipment, can solve the problems of low working efficiency and time waste caused by manual water pumping in underground small water accumulation point drainage, and comprises an automatic drainage controller, a liquid level sensor, an electromagnetic valve and a drainer, the drainer comprises a steel pipe, a steel plate is arranged at one end of the steel pipe, and a through hole is formed in the steel plate; one end of the connecting pipe is connected with the penetrating hole, and the other end of the connecting pipe extends out of the two-way I. The end, located on the steel plate, of the connecting pipe is connected with an elbow, the other end of the elbow is connected with one end of a two-way II, a through hole is formed in the surface of the steel pipe, and the other end of the two-way II is connected with a static pressure water pipe or an air pipe. The output end of