Automatic drainage device for compressed air pipeline

The utility model relates to an automatic drainage device for a compressed air pipeline, which comprises a water storage tank and a mechanical steam trap, the water storage tank is communicated with the compressed air pipeline through a first pipeline, the first pipeline is provided with a first isolating valve, the bottom end of the water storage tank is provided with a bottom water discharge pipe, the bottom water discharge pipe is provided with a water discharge valve, and the mechanical steam trap is communicated with the water storage tank. The mechanical steam trap is communicated with the top end of the side face of the water storage tank through a second pipeline, and a drain pipe is arranged at the rear end of the mechanical steam trap. Impurities and accumulated water are automatically separated, the accumulated water is discharged through the mechanical steam trap, blockage of the mechanical steam trap is effectively reduced, and it is ensured that the accumulated water and the impurities in the co